No LTE coverage - Telkom won't cancel my account

In August 2016 I took a LTE contract with Telkom, almost immediately I have coverage issues. Logged numerous calls with Telkom Tech support and no one came out. I installed an outdoor antenna at my own cost and still the line would drop. I took the device back to Telkom and ask them to cancel my contract, I filled out a cancellation form and offer the device back to them and they refuses until Tech support confirmed the quality of the line. They never called on me. I disconnected the device and made numerous calls checking on the status of my account. Today my bill sits at R11k, The two year contract has expired in August this year. Tried cancelling my contract and they say it cannot be done because my account is suspended and they continue to raise charges to my account. They want me to pay the account in full and then raise a dispute. Are these fools for real.