Where is it possible to use the Promo Card I received for wireless boo deal when I switched to ATT?

My fault for agreeing to change to ATT mobile, but the "sales person" misrepresented the agreement, the promotions, the trade-in on our previous phones and especially the "AT&T Trade-in Program" with the "Promotional Card" that could be used at restaurants, retail stores, etc.  I attempted to use the card today at a restaurant and "not accepted".  So, got online and searched for info and discovered the "trap" that it can apparently only be used to pay to AT&T .. in other words "give the money back to AT&T for items I don't need or are high-priced.  Also, although I was told the "service" on the phones would be as good as my former service.. NOT..  I've let many others it ain't worth the trouble and time nor for the "promotional" sales pitches and will continue to advise others of what I've experienced.  Just to let you know.. Sales I do myself..  I DO NOT, and would never, give misinformation to my customers whether it means a "sale" or not.  It's also backing up what you sell and the best possible service after the sale.. 

@npofnc  This is an 8 year old thread.  If you have a question, please start your own thread.  This one will be closed.