T Mobile Took My Phone Credits

So I upgraded my iPhone 13 to the iPhone 15 Pro upon ordering the lady sent me one with the wrong memory so upon receiving it I called them exchanged it for iPhone 15 pro with The largest memory they gave me buyers remorse, even though it wasn’t my fault upon exchanging the phones they took my credit away for my trade-in because their system messed up upon doing that I have to wait three months to get my credit now so I’m inconvenienced because T-Mobile system didn’t recognize it as a trade in  and took my trade in phone credit back absolutely ridiculous!!!!