I Feel Cheated and Deceived with T-Mobile lies and false advertisement.

My wife has a iPhone 12 that was fully paid off from T mobile and was just laying about in our home. We went to Jamaica for 3 days and when we returned T mobile charged us $700.00 for roaming whilst overseas. We paid $500.00 and was placed on a payment plan for the additional $200. We called T mobile to unlock the sim lock that was placed on the old iPhone twelve , because we are going back to Jamaica and we don't wanna incur the $700 roaming charges again. T mobile basically informed us that even though the iPhone 12 is fully paid off , we would have to settle the $200 payment before they could remove the sim lock off the old old iPhone 12 .   They are basically holding us hostage …. Seems like we're gonna have to pay an additional $700 again when we return from jamaica. They are very dishonest…