Cell C Data Card Offer ??????

I receive a phone call from Cell C – offering me a Smart Data Card 10GB-10GB for R279.00 On special for 24 Months. I took it for my daughter. Last month I received a bill for R17,000 . I query it with cell c – they state I have an open Data Card month to month. They send me a record, showing data use in morning hours, my daughters is sleeping that times. I am not getting anywhere resolving this. Sitting with a bill of R72,000 My daughter of 9 years uses it – she will never be on FB – here phone don’t have it or opera Mini . I request a recording. Why will I have an open data if I can take a uncap offer. This is frustrating causing debit orders to bounce back lack of fund. And going to lower my credit score. Cell C doesn't have a ***** line, nor a ***** e mail address. they will e mail me back, stating this was a open data card. How come offering me a smart data 10GB? I send them proof of the activation contract, e mailing me back I must make an affidavit to to get the contract?? I show them proof it is not month to month it was a special for a smart data 24Months. They say I can go to a cell c shop listing to my recording. I even ask the lady if the 10GB is finish can I top up. Yes was her answer. I feel frustrating not get help from cell c. Sending Proof of activation contract which was done telephonically. Proofing it is not month to month. proofing stating it a 10GB. I have been a Cell C Customer since 2003- this is poor service, no investigation - no customer service no help.