Dissatisfaction

I have had a bad experience with Cartrack. I have been with the company for almost 4 years and in that time I only skipped one month and therefore made an arrangement for them to take that money in January this year. They then sent me a debit mandate for the amount I was behind and I agreed to it the next thing I know I was debited 4 times in one month and when I called them they would not give me an answer instead to say I owe arrears that I'm not even aware of . I then asked for my contract and recordings of the arrangement and the conversations had with them and was told they would send them but to date nothing. I sent an email to the CEO and got a response the same day but it's been two weeks and still nothing. These people are to get an installment this month and I don't trust them to do the right thing anymore. I'm very unhappy with their service and feel my rights have been violated