Traded in iphone 12 mini and tmobile claims it was damaged

Traded in my Daughter's iPhone 12 mini in near perfect condition (I know because I'm the one that transferred her data over to her new phone, wiped down her old phone, left it in its case, and then packed and shipped it myself) only for them to claim they received the phone damaged. In the pictures they provided her case isn't on the phone anymore and the phone has fingerprints and grime all over the screen. Like I said before, I cleaned the entire phone before packing. It was clean all around, not a fingerprint on it. So now, instead of the $999 credit, they're offering me $43. What a complete scam!! Something is not adding up.