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

The same thing happened to me.  I have receipt of them receiving my device; also, phone calls from a few different t-mobile reps. that the they received it; however, can not find it....... Won't give me credit for it; while at the same time raised my bill, tremendously (I was suckered into all the gimmicks) to get all the discounts!!!!  If this happens,-- this much, isn't there something we can do!!!!