bill after phones are paid off

It will take a billing cycle to see the change.

I'm curious about this too. My previous IPhone I had for 3 years was definitely paid off when I traded it in. They told me when I bought it that I could get the extra charges dropped after it's paid off, if I came into the store and requested it 

I traded my iPhone 11 for my current 14, and you know that limbo month where your bill changes? Actually decreases. That means the phone is paid off and has been. Then the next month it's back to what you're used to. 
 

Maybe I’m alone with experience, but the whole transaction was weird to me. 

When your EIP(s) are finished, your bill will decrease by the amount you were paying monthly for those EIP's.  If you want to change your plan for something cheaper, if available.  You can.  

I bought this iPhone 11 @ Walmart fully paid for and just noticed that u too have been billing me for a phone that was already paid for. Now the phone guy at Walmart activated to my account with you guys but I shouldn't have to pay twice for the same phone

My phones and watches have been paid off for 3 months.  My bill hasn't gone done at all, I'm calling T-Mobile today.