Incompetence of account department

I don't know how many times I should send cartrack my proof of payment. On the 26th of June, I paid R216 via their link and used card payment. They came back said .you account is due, I se t them proof of payment, ot once but 5 times and everytime they say they will allocate. As it stands, they debuted an extra R100 from my account yet I still owe them. Maybe I should get legal opinion on how to cancel their contract. I cant be harassed daily for something I paid almost 2 months ago. They have the money, proof of payment but their *********** account department cant allocate the funds to my account.