AT&T does not honor its promotional offers.
My husband and I switched to ATT from Verizon in October because they were offering a promotion of $650 to port your lines over at that time. We were told by the sales person in Rockwall, Texas that we only needed to port our lines over, not buy a phone to qualify. I bought a phone anyway and my husband kept the one he had. We were told repeatedly that we would get the full credit whether we bought phones or not. I have made calls every month to ATT because this $650 credit has never shown up on my bill. Every time I call I am assured it will be on the next bill yet that has never happened. If this doesn't get resolved now I will be filing a complaint with the FCC and the Texas State Attorney General's office.