Being charged for device tmobile received but cannot locate

Holy cow! I am going through the same thing right now. Upgraded my device at the T-Mobile store here they took my old phone and away I went. I realized something wasn't right with my bill (unfortunately 4 months in) and realized they were still charging me for the phone I traded in plus my new one. I've been given the run around for the past two weeks now. Basically the same thing they are telling everyone else "we can't locate it" etc etc. so frustrating and it's very obvious by all of the similar stories there is a bigger issue going on behind the scenes. I've been a customer for almost 5 years now and I cannot believe I've ever recommended these people. Ridiculous!