Constant Debits

My contract with Heita end 2015,after that they kept debiting on my account and I went and complain and my money was paid back.this year they have started debit again and iv been reversing the debits every month and it's different amount and the small amounts I have not reverse .I went to Telkom store they said they can't do it in the store so they will lodge a query and someone will call me and the matter will be sorted out.it's been 3 months already and the debits are still not stopping.#I want my money back.Please can they sort out this issue asap as it reflects on my debts.