Returned my devices in the Trade In Program but ATT will not give me my refund!!!

I traded in 2 iPhone 11's and sent the phones into where I was told to send them and AT&T refuses to provide me the monthly trade in value as agreed as they state the agent who took the order did it incorrectly.  I have asked for my old phones back or the credits earned and I am being refused both.  Do we need to have a (Edited per community guidelines) (Edited per community guidelines) as this seems to be a large issue with many customers.