Account billed without service being provided and intermittent tracking device

I had a tracker contract from 2012 which was for 3 years. The contract expired in 2015 and to my knowledge the company should've stopped debiting my account. They continued debiting my account for a good 2 years but the tracker was not working. I kept on trying to press the panic button but no response was received. I called in several times and they advised they cannot track my car since it was not in motion. I decided to test the tracker again at the start of November and still no response was received. I called in and I asked why is it that I do not receive the response from pressing the panic button. I was told there could be a technical problem with my tracker and according to their records my contract has expired. So they were deducting my money for 2 years without providing service? If I calculate the premiums, they sum up to R4600.00. The consultants I spoke to during this month of November advised that a manager will call me back in about 48 hours time. Till to date I'm still waiting and it's almost 3 weeks later. I need my money paid back for their horrible service. I always thought I was safe especially at night time but NO, I'm paying for nothing. I don't even need an explanation from Altech Netstar, I need my premiums from the day my contract expired to date paid back.