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

I am in the same boat.  I traded in an iPhone 6.  Was noted as “received” on the UPS tracking site.  I followed the same steps, printed the shipping label as directed.  Still no acknowledgement from T-Mobile that the phone was received.  Very shady business practices.