******** debit of bank account / DSTV's refusal to cancel a contract which came to an end

I entered into a price lock contract with Multichoice which came to an end September 2019. On 3 October 2019 I contacted the call centre and cancelled my DSTV subscription. Despite cancelling my account my bank account was debited again on 3 November 2019. On 4 November 2019 I emailed DSTV at *** and at *** to inform them that they should not debit my account again as I have cancelled the contract. I even received an email from *** under reference number: ***. December 2019 my account was once again debited and in January 2020 which debit orders I sent back. Since then Blake Associates keep calling demanding that I give my personal details (ID, bank account number) and that I owe multichoice. How many times should I cancel a contract? My next step is to refer this matter to the consumer tribunal. Maybe if Multichoice receives a costs order from the Tribunal they will listen.