Sprint complaint: I did nothing wrong but my former carrier is sueing me because Sprint did not follow throug to get the phonesphonesh

Sprint was ran a promo that they would pay up to $650.00 per line to switch to them.I called and I was accepted. I ordered the phones, took the old phones and final bill in to the store, they activated the new phones, and turned the ATT phones back to factory settings.Asked if I needed to do anything else was told no they would handle it. Next thing I know I am being sued by ATT for non payment.when I went to get the 2 phones I was told they would not except, there were all 4 phones and the final bill laying in the back room.nothing had been I called ATT today and nothing has been paid.The man at Sprint will not. take my calls,this is on my credit report and I have been. Lied to put off and spoken to rudely.I do no think much of their word or do I have respect for them.There was no need to lie to me nor bring down my credit, I am still paying my bill even though I can not get my email on my IPhone. Sprint you should be ashamed.