Phone still locked after trade in and 2 years of payments.

Getting ripped off by AT&T.  The iPhone 12 pro max was $1099, I traded in my phone for $800 credit, paid $37 a month for 27 months AND they think I'm going to pay another $600!

The pro max BASE PRICE was $1099.    W ith terabyte storage was a $1600 phone. 1/2 terabyte was 1300. Installments are 36 months. 

The $800 in bill credits is over 36 months.  If you pay off early, you must pay off the full balance left. 

There is no way you made 27 payments on a phone that was released 24 months ago.

It seems AT&T is correct. 

The phone has been paid off! They will not unlock my phone.

No it hasn't.   

Read the information including the installment information that's on your bill.  It will tell you the full amount of your phone's purchase price, how many payments you have made and how many payments are left.

FYI, the iPhone 12 pre-order was a month late in 2020. 

Hello Jemoran78, let's take a look at your installment plan.