Bad treatment

I have an account with Jet Stores / Edcon for a while now. I happened to be charged for airtime. every month for more than a year. I was not sure what it was about, since I never authorized nor received the airtime. Late last year I asked that this should be stopped, and it was eventually stopped. I also requested that all the amount I was charged be credited back to my account, but there has no response nor any movement to correct this. All I am looking for right now is to have my money paid back.