Solved! If I bought a us cellular phone and didn't activate it with the us cellular sim card, can I use a sim card from at&t as my car

Mar 31, 2018
I bought a us cellular phone years ago but I never signed a contract or activate the phones with us cellular, but I am activated and signed to at&t. My current phone is already paid for, and I'm due for an upgrade, but I don't want the monthly payment. Can I just switch sim cards to the us cellular phone and be alright? Or will us cellular somehow know I used their phone and charge me?