unfair practice

I had a contract with Nestar in 2018 April for my car, in June I was nearly hijacked and Netstar did not want to assist, I then had to cancel the contract and paid all the penalties as per the contract, now in January 2019, I see on my bank statement , Netstar is debiting money and when I called I was told that they are investigating since I am owing them, again this month they have debited and I have changed banks but now I have bank charges to pay since I did not provide for that debit order, I want Netstar to pay for the bank charges and give me proof that I owe them.

regards Noma