Being screwed over by AT&T

I bought the Samsung Note 7's on a BOGO deal through Costco in Aug. 2016. Everything was going great until the Note 7's were recalled and we had to return the phones and choose something else. We returned the Note 7's in Dec 2016 to the Costco kiosk. The representative there told us to get the BOGO deal on the new Iphone 7's that we were purchasing she would cancel the new line of service that we started with the new Note 7 and start a new line of service for the Iphone 7.  She had to make several calls and was hung up on 4 or 5 times before she ever got that done while I sat and waited for over 2 hours.  So now I have contracts for 2 Iphone 7's for the BOGO deal but I have not received any credit for the free phone since purchasing in Dec. 2016.  AT&T back office, escalating team, Supervisors, whatever they are called want to say because the the Note 7 number was dropped I am not eligible for the BOGO deal on the Iphone 7's.  I did not ask for the number to be dropped, this was done by the phone representitive.  I have called AT&T for the past few months inquiring about this.  Have been told different things, from being told I would receive a call bac,, (NEVER HAPPENED) to it being esculated. I have been a customer for numerous years. Right now I am NOT HAPPY!