Cancellation if Cell Line due to dispute on Data C

I have three contracts with Cell C. The first contract is a stand alone. I have another Cell line which is suppose to be a stand alone line, and then I have a data contract of 5gb. I took out the Data contract at the end of May, once my account was debited I already queried the data line usage. In August my wif-fi was on for 3 hours, but with the Internet off, in the three hours I used up the entire 5gb??? How is this possible, I stopped using the data because if I switch on the data it just goes missing. Cell C combined the two lines (data and cell line) into one contract, this I did not request. With the dispute that is ongoing because they cannot tell me where my data disappears to, they have now disconnected my Cell phone, although it is paid for, and will not unlock it due to the outstanding amount on the data line, that I am disputing. They are robbing me. Now I am losing business due to the lack of a working Cell line. What am I suppose to do. They refuse to in-link the two lines. I am disgusted in the service and with my contract ending soon, I am for sure cancelling the contract with Cell C.