Assurant return concern

In the last 2 years I have had 2 warranty replacements and 2 broken screens.  The last one, a warranty replacement was lost in house by T-Mobile.  It was shipped UPS 3rd day with a provided label.  UPS confirmed delivery to Ft Worth and was signed for by T-Mobile.  Unfortunately, T-Mobile does not document the opening of received boxes and the only record they have is by scanning the phone for the IMEI.  Mine was never scanned so now I am charged $860.50 for their error and sloppy bookkeeping. It would have been no better if I requested a return receipt because that does not prove that the phone was in the box.  Also shipment is only insured for the minimum $100.  Of course, if T-Mobile loses the phone as they did in my case, it would not be covered either.   I talked to 4 "experts and 2 supervisors and the best they would do is knock off a couple hundred bucks.  I was told I should have returned the phone to a local store, however, when I made the claim, I was told I could not drop it off at a store. Next T-Mobile said that was done because the local store was closed, which was not true.  I Did drop by the store 1 mile from me to help transfer the data, but they were not permitted to touch a phone because of the Wuhan virus

I am disputing the charge and if that does not work, I will sue them in Small Claims Court.  I also contacted my Congressman who is considering consumer protection legislation for situations like this.