Cell C
Billed incorrect amount for a R99 2gig contract

Hi,
I was called by Given from CellC with a data contract offer for R99 per month x 24, got the SIM card on the 5th of the month so the debit order rolled over to the next billing cycle, I did not use all the data on the contract so in all truth the amount for the 2 months is R99 X2, but i got debited R522.01, upon querying this I was told not to reverse the debit order because CellC was going to fix this with no problem, I have called them a lot of times and I always get transferred from one person to the next. One lady told me that Given made a mistake by not loading discounts on the contract and this would be fixed and a refund would be due to me, but that hasn't happened either.
Why is CellC providing such a bad service to their customers.