I had sent my old device iPhone 6 Plus to Tmobile for a trade in credit. The tracking # showed Tmobile warehouse already received it but no credit was issued. I have been contacted customer service so many times and they said they didn't receive the

Even I had the same issue with trade in device not received at warehouse. I have sent samsung s9 with the given return label and was delivered by usps. After few days I got an email that my phone was not received at the warehouse and my promotion got cancelled. After a lot of communication with Tmobile customer care they said to check with usps and don’t want raise an issue to escalate it. I don’t know how to take this process further and I don’t want to pay the money for someone else mistake.

I see there are lot of similar issues about trade in device not being received and I didn’t see positive response to the replies. 

can anybody please me on this?