Zero customer service

My husband took out a contract with you guys early this year for his bakkie. In June he sold the bakkie and notified Cartrack and was advised that the person who bought the bakkie can take over the contact. Relevant documentation was signed by both parties and sent back to you guys. However almost every day he receives a call from your collection department and he keeps repeating one thing, that he has sold the bakkie and sent you documents for the new owner to take over the contract and make payment. I'm sure he has said this more than 100 times to over 50 people but clearly it's falling on deaf ears. Today a debit of about R900 went off. Please reverse the debit as it is unauthorised. I wonder what is your response time when cars are ****** cause when it comes to handling queries it is very very slow.