How to escalate a complaint

I have had similar issues. Supervisors NEVER call back. They promised to pay off my Verizon phone if I switched - then the small print. Actually you get a prepaid visa to pay it off. But from Day 1, there was a "problem with the submission". But we will get it fixed - just have to wait 15 - 30 days. Ok. 30 days go by - nothing. PHone call - oh, there was a problem with the submission. We will get it resolved but it will take 15 - 30 days. At 30 days you get a call saying there was a problem with the submission. What's the problem. Well its a problem in our system but I will get it fixed - 15 - 30 days. The last two times I asked for a supervisor. I was told they are on a different phone system but would call back within 15 minutes. They never call back. OK this time we PROMISE they will call back. No call back. I have filed with the BBB and will work on reporting fraud not to the FTC. They did the same thing to my Fiance - he never got his refund.