Car Track disputeCon

I have sold my vehicle nearly two years ago to We Buy cars. I did have a monthly contact with Car track for R99 per month. I had to sell my vehicle as I could not continue working due to Contractors closing etc. I sold my vehicle almost 2 years ago (June 2018) and has not been able to get Car track to stop putting debit orders through on my account. Also the amounts they have been submitting debit orders for is more than sometimes 3 times my original contract. I tried to stop the debit order at the bank but due to the fact that they keep on changing the amount I have not been able to do this. Every time they submit a debit order and there is no money in the account the bank also charges R150-00 for no funds. This sometimes happens up to 3 times a month. As I mentioned this has been going on now for almost 2 years. Please help. I am 66 years old not working at present and batling to survive.