Charges for undelivered Standard Bank Simcard I

Standard bank sales approached me for their sim card with no cost but with free data and airtime. I agreed for delivery in November 2019, unfortunately I never received it to date. To my surprise they started debiting my account on undelivered simcard from then to date. The agreement was that the charges of cheque account will be the amount of airtime @NO Costs. When calling to cancel the deal they never answer their lines . So I am sitting with a monthly debiting of R89 monthly. The only option is to reverse the debit order but I still incurring charges.