Samsung Trade in through T-Mobile gone wrong

I pre-ordered a Samsung S 24 Ultra through Samsung website, but ordered the T-Mobile one through a promotion they were running with Samsung. I traded in my unlocked S22 Ultra purchased through Samsung 2 years prior. T-Mobile sent me shipping label, i returned the phone through UPS. Tracking showed TMO GRC received my phone on February 13th. February 16th i received text from 456 Tmobile saying they received my trade in device and are processing. I received the first bill credit. 

Now to this month. I lost my bill credit. Tmobile says they didnt receive my phone. I showed them documentation where the phone was sent through UPS and their label, delivered by UPS and received by Tmobile. Theyre claiming they do not have it in their warehouse and are not giving me the credits. Then came back and said no promises, but they will escalate the issue. No promises? T-Mobile is jacking me for $1000. I have been a loyal customer since 2009. This is very disheartening. I am not sure what else i can do?