Trade-Ins Not Received - No Help From AT&T

Hello, 

We ordered 2 new phones in July, under the assumption of credit for our trade-ins (a total of $1600, $800/phone).  I used the pre-printed label supplied by the company, and followed all instructions to a T, and handed both boxes to the agent at our local post office.  Now, AT&T is showing they never received the trade-ins.  If we want to dispute, we have to provide a tracking number.  I don't have the tracking number, as it was on the pre-printed label that I used to send in my trade-ins.  AT&T claims that they cannot find the tracking number on their end, although they provided the label.  I have heard from several people who experienced the same situation that AT&T CAN look up and provide the tracking number, but routinely refuse to do so.  We've so far been hung up on and lied to by multiple AT&T customer "care" specialists.  

I've so far filed a claim with USPS, and my next stop will be filing with the FCC and BBB.  

This is our first experience with AT&T, and will definitely be our last.  I'll also be sharing my story with friends, family, coworkers, and anyone who will listen.