Rewards Card Redemption

Ive signed up for Uverse and cable last year sep.23 and was told that I was eligible for 150$ reward card. But person who served me said that I had to wait 6months before redeeming the card, and a remember pretty good. The only problem is that I never was told that It will get expired after particular time period. Time past and of course  the reward thing got out of my mind for a while until I accidentally found my paperwork that I signed that day, so I thought it was a good idea to finally get the rewards and use them. Took me 50 minutes just to reach somebody after I was told that everything is expired and it wasn't their problem that i didn't redeem it before.. but wait, now they are telling me that I had to get it within 60 days and that's the most it last ..they were rude and stuff but I got used to by now.. 

Just one last question, is there a way to somehow  get that credit  put on my account as a balance so I could  pay my monthly ATT bill with it ?