Netstar is not reliable ! stay away

I sold my car and have been trying to cancel the contract for like 5 months now. Netstar was still debiting from my acount, fortunately I managed to recover my money through fnb dispute. I ultimately left the country. After several attempts, the finally responded to my emails, telling me that I need to pay a cancelation fee of R1354, without explaining where this amount comes from. My insurer was paying them and they never told me about these policies. I am extremely disappointed on netstar. I paid the said amount and I requested a proof of cancelation letter from them, because I don't trust them. They might try to debit again.