Bad Service & Inability to sort out account

I've taken out a data contract with Cell C in May 2015, and was not billed for the first 3 months. On the 4th month my bill was approximately R1200 and kept escalating by R1000 every month. Through enquiry with Cell C I was informed that this relates to the data usage, and that the account was capped at R15000(amount I was not informed of, at the time I took out my contract). I queried the non billable amount for the previous 3 months but was not given a suitable response on that.. The first month was paid via debit order and I queried the 2nd and 3rd debit orders and was informed that the data usage department will be contacted to supply me with a breakdown of my account. A breakdown was received, but with missing website addresses/IP addresses so sites visited could not be traced. I have phoned CellC almost every single day query this and was shunted from pillar to post (from *********** call centre consultants, to accounts and legal departments that don't answer phones. I have still not yet managed to resolve this issue. I cancelled my data contract but Cell C has now suspended my phone line on another account for the unpaid amount, after telling me they will investigate