Netsar: Claims money for service they not rendered

I had three year contract and finished the term. 1. I tested the devise in few six months before end of my term they said it is not active. 2. But while finished the term the continue with deductions. 3. I had to renew the contract where they say they will come to fit the new device they never come for a period of 7 days. 4. Then I had to cancel them and try another company that responded with in 24 hours with device fitted. Now they say I owe them money R260 but they never come to fit the track device in my car.

I am so confused and disappointed