R10 000+ deducted from account for Cell C mistake

About 3 months ago I was contacted by someone at Cell C and told that my wife's account will be blocked as she has a bill of R10 000+ due to data usage. She has had this account for about a year and a half and her monthly payment is about R500 so this had never happened before. Upon contacting Cell C we were told the data usage occurred on Google+ which my wife does not use. A query was sent to Google by Cell C and eventually Cell C returned to us and said there was a mistake (phone had been hacked somehow and data ******) and that Cell C would not deduct the R10 000+ from our account because the billing department would be contacted. About a month later when checking our bank account, my wife noticed a debit by Cell C for the R10 000+ amount. Cell C was contacted, but the woman who had been helping us could not be contacted as there were 'technical problems' in the Western Cape area. About 10 calls on different days produced no results. Each technician spoken to would take down my name and number and inform me that I would be contacted. To this day I have not been contacted and have not been refunded.