US Cellular Early Termination Fees After the T-Mobile Merger: What You Actually Owe

The text says US Cellular merged with T-Mobile and nothing changed. The next bill says you owe $612. Both are true.

The "early termination fee" most US Cellular customers hit in 2026 is not a service-plan ETF. It is the remaining balance on a device installment loan, plus any promotional bill credits you forfeit on the way out. T-Mobile closed the acquisition on August 1, 2025. The marketing said "same or less." The device loan you signed in 2024 said something else.

This is what you actually owe to leave US Cellular after the merger, why the device balance survived the deal, and the one piece of leverage most former customers do not know they have.

TL;DR

• US Cellular's wireless operations became T-Mobile on August 1, 2025. Device installment loans signed under US Cellular are still enforceable under their original terms.
• Most "ETF" charges on a final bill are actually the remaining device balance plus forfeited promotional credits, not a true service termination fee.
• T-Mobile's Keep and Switch program reimburses up to $800 per line on device balances and ETFs when porting in from an eligible carrier, including UScellular. The reimbursement is a virtual prepaid Mastercard within 15 days, capped at 4 lines, expiring in 6 months.
• Pay off the device balance, request the FCC-required unlock, then port. Skipping a step costs money.

What the merger actually changed

On August 1, 2025, T-Mobile closed its $4.4 billion acquisition of US Cellular's wireless operations and spectrum. Approximately 4 to 4.5 million postpaid and prepaid lines came with it. T-Mobile committed publicly that US Cellular customers would pay "the same or less" for their rate plans during transition, and that service would migrate to T-Mobile's network over time, with roaming filling the gap.

The corporate plumbing is now T-Mobile. The contracts you signed with US Cellular are not. Two things continue under their original terms:

The device installment loan. If you bought a phone on a 30- or 36-month installment plan, that loan is a closed-end consumer credit contract under the Truth in Lending Act. Mergers do not extinguish closed-end loans. The remaining balance is still owed.

The promotional bill credits. If US Cellular advertised "$1,000 off with trade-in over 36 months," the credit was structured as a monthly bill discount that only continued while you stayed on a qualifying plan. The merger did not erase the discount. Canceling service still ends it. Switching plans in a way that disqualifies the line still ends it.

What the merger did change: the legal entity collecting the balance, the customer service routing, the billing portal URL, the name on the envelope. None of that changes the math.

The "ETF" line on your final bill, broken down

When a former US Cellular customer cancels service in 2026, the final bill typically has three line items that get bundled together in conversation as "the early termination fee." They are not the same thing.

Remaining device balance. This is what is left on the device installment loan after the last partial month of service. On a 36-month loan for an $1,100 phone bought 12 months ago, the remaining balance is roughly $733 before tax. There is no proration or discount for leaving early. The full balance becomes immediately due.

Forfeited promotional credits. If the phone came with a trade-in or new-line credit spread over 36 months, those monthly credits stop the day the line is canceled or moved to a non-qualifying plan. They are not refunded. Future credits, the ones you have not collected yet, simply vanish. On a $1,000-off-with-trade promo at month 12, you walk away from roughly $667 in future credits.

Service ETF, when it exists. Most US Cellular plans in 2026 do not carry a separate service ETF. Some legacy plans and connected-device contracts do. Where it exists, it is typically a flat dollar amount that prorates down each month of service completed.

The bundled "$612 balance due" your bill shows is almost always the first two, with possibly a small partial-month service charge attached. Use the early termination fee calculator to total the three components honestly before you decide whether to leave.

The Keep and Switch reverse-payoff, post-merger

T-Mobile's Keep and Switch program is what most consumer-facing coverage of the merger missed. It reimburses up to $800 per line on the remaining device balance and any ETF when a customer ports in from an eligible postpaid carrier. UScellular is on the eligible-carrier list. AT&T, Verizon, Spectrum, Xfinity, Claro, and Liberty (Puerto Rico) are too.

The mechanics:

1. Activate a new line on a qualifying T-Mobile postpaid plan.
2. Port your existing number from US Cellular within 60 days of activation.
3. Submit a final bill from US Cellular showing the device balance and any ETF.
4. Have at least 90 days of device payment history with US Cellular on the line.
5. Receive a virtual prepaid Mastercard within approximately 15 days. Maximum $800 per line, up to four voice lines.

The card has no cash access and expires six months after issuance.

Post-merger, this creates an unusual situation. A former US Cellular customer whose service has been migrated to T-Mobile's network as part of the integration is technically already on T-Mobile. Porting to T-Mobile "retail" via a Keep and Switch offer requires that the back office treat the line as a new switch from an eligible carrier rather than an internal transfer. Some customers report this working cleanly. Others report being told the offer does not apply because the line is already T-Mobile in the system. The honest read: it is worth the call to a T-Mobile retail rep before you cancel, but do not bank on it.

The trap inside the offer: "up to $800" rarely covers a full late-model device balance. An $1,100 phone bought 12 months in still leaves you about $733 of device balance plus a few hundred in forfeited credits. The $800 reimbursement covers the device portion. The forfeited credits are still gone.

The FCC unlock rule, finally enforced

Here is the rule the FCC made carriers agree to and that took meaningful effect in 2026.

Once your device installment plan is paid in full, your early termination fee is paid, or you have completed your prepaid usage requirement, your carrier must unlock your phone within two business days of the request. Automatically. No extra fee, no requirement to stay a customer, no required port-in.

What this means for former US Cellular customers: the day your last device payment posts, file the unlock request through T-Mobile's support portal (the entity now servicing US Cellular accounts). Wait two business days. Verify by inserting another carrier's SIM. Do not trust "it will unlock automatically." Confirm it before you port out.

A locked phone is worth less on the resale market, useless on most international networks, and frustrating to troubleshoot with a new carrier later. The two minutes to file the unlock request is worth more than any other step in the leaving process.

The clean-leaving sequence

Five steps, in order. Skipping any step costs money.

1. Pull your current device payment status from the T-Mobile/US Cellular app. Confirm the remaining balance, your loan terms, and your monthly bill credit, if any.
2. Decide whether to pay off the device balance in full before porting (cleanest), keep the device loan open and pay it down month by month (cheaper short-term, but you stay tied to the carrier billing relationship), or trade in via Keep and Switch (cleanest if eligible).
3. Once the balance is paid, file the FCC unlock request. Wait two business days. Verify with another SIM.
4. Port your number to the new carrier before canceling the US Cellular/T-Mobile line. If you cancel first, you can lose the number.
5. Keep the final bill, the device-loan payoff confirmation, the unlock confirmation, and any Keep and Switch submission paperwork for at least one year. Disputes about post-merger billing run on a longer timeline than they used to.

If the final bill includes a charge that looks wrong, dispute it in writing with T-Mobile customer service first. If they will not budge within 30 days, dispute the charge with your card issuer under Reg Z if it is a credit card billing error (you have 60 days from the statement date). If the line was on autopay through ACH, the Reg E timeline is similar but the dispute rights are narrower. Finally, file a complaint at fcc.gov/complaints. The carrier has 30 days to respond formally, and the open complaint frequently produces a quiet adjustment that the regular dispute path did not.

The contract you signed survived the press release

The press release said "exceptional value, superior 5G experience, unparalleled benefits." The device installment loan you signed at the US Cellular store said "the unpaid balance of the retail price of the device will become immediately due and payable" if you cancel before the loan is paid. Both sentences are still in force in 2026. They describe the same transaction from different angles.

A US Cellular early termination fee is a special case of the device-loan-as-ETF shape that runs through every modern wireless contract. The merger added a temporary reverse-payoff path and changed the name on the bill. The math underneath did not move.

Redline reads contracts in plain English. Photograph your US Cellular service agreement or device installment loan, paste it in, or upload the PDF, and Redline flags the device-loan clause, the promotional-credit terms, and the unilateral-change language in seconds. One scan, one dollar. Available on iOS and Android.