No communication from AT&T

So what is someone to do when they have contacted ATT nearly 10x's and never received the credit they were offered in the store?  Not only did I message them through chat, I called and spoke directly with several people.  I kept getting transferred and then when I finally would get someone, they would 'promise' to call me back but never would.  I actually went back into the store, they submitted a claim and I was told they would get back with me, but nope.  This has been going on since the end of November.  Any thoughts I what I should do?