Assurant return damaged device package Empty!!

same exact thing is happening to me. i broke a phone had assurant send me a new one. the one they sent me was damaged when i got it , it had a burnt screen so tmobile sent me a new one. i setn back both phones and months later they hit me with a 2600$ bill for two note 20 5g ultra. ive been told they found one then a month later i was told by a manager that NOT ONLY 1 BUT 2 PHOONES GOT SENT BACK TO THEM BITH EMPTY PACKAGES!!!!!  mind you one i dropped off at fedex and one was dropped off at ups. i did not package either phone i showed up to each store (fedex and ups) i showed them the email they scanned the QR code i handed them the phone and i paid the fee and left… i checked the tracking and both ttacking numbers had weight of 1.5 lbs and both were signed for now i am in a dispute with tmobile…. they have magically found one of the phones but they are trying to stick me for the other one. i habe contacted consumer affairs and was sent to telecommunication and cable department. we’ll see what happens but ive found countless stories online of the same nature. could you please let me know what you did and who you contacted to get a resolution? thank you