Cartrack spamming and deducting money without authorisation

I bought a car from Penta Suzuki which already had a cartrack unit fitted. I declined the cartrack contract when I purchased the car. Later the month on the bank I had to approve a demand deposit for Cartrack which I declined. I have sent numerous e-mails asking for a copy of the signed contract but have never recieved it. Cartrack keeps on phoning me where I expalain to them the situation but nobody can help me or has sent me the contract. Suddenly on my bank account they were able to deduct money without my authorisation. The phone calls from cartrack are non stop and this is becoming a problem. All I ask is if there is a signed contract please e-mail it to me so that I can understand why you are deducting money from my account. If there is no signed contract please return the money into my account and stop phoning me!!!!!!!