AT&T wont honor promotion for note 10

I was with sprint and looking for a new phone when I seen on their website a promotion in November. The promotion was basically a free note 10 with trade in that would give you a monthly credit covering the cost. I noticed on my bill I havent been given this promotion and called support and was informed that they have no record of this promotion. Any advice on what steps I can take to get this settled, i feel as if I was tricked into this new contract.