Promised a reward and never received it

I purchased AT&T Internet and the sales representative said that I would get a $300 rebate. When the email came for my rebate or/reward it said to enter my last months bill from my previous Internet provider. I had not had a prior Internet service. I was unable to submit a bill due to not having any other service prior to the AT&T, so I called and got passed around several different departments, and was told I needed to wait 30 days of my current bill with them and then submit that one.  So I did, and I submitted my bill, but received an email saying that I am denied my reward. I have called multiple days in a row be on hold from anywhere to 30 minutes to an hour with no solution. I’ve use the online chat system, no one is able to help assist me. It’s very frustrating to be told that I would buy some thing then I would receive a rebate, this is what drew me to purchasing AT&T fiber instead of other services. Now I don’t get my money my bill is high and no one wants to help me. It is extremely frustrating that you cannot email anyone and they require you to call 8 to 5. I don’t have every day of my life to wait on hold. It is false advertisement and it was never explained that I had to have prior services anywhere. I wish AT&T would reach out to me and try to solve this issue.