Cancellation of Data and double billing.

I called Cell C to cancel the 2gid data and get 1 gig data. they billed me for the 2 gig data and deducted it from my bank account. Then I called on the 31/07/2015 to cancel the data on two of the phone lines. The lady there said that she could not cancel it as it was part of my package, we had some words and now I was billed again for the same period for the 2 gig and the 1 gig and for the data that I cancelled where I was told that it was part of the package. I have sent them mails everyday last week. The just send back a message to say that they are looking at the query. How long is there turn around time?? But the deducted the amount of my back account again. I need a credit and I would like to have this matter resolved a.s.a.p. THANKS