Prepaid service debits amount from your stored debit card information (wrong)

Excellent service until they automatically deducted from my debit card, The reason i signed up with prepaid fibre is so that if I cant afford to pay the next month then i don''t make payment.. well thats what was told me... recently because they store your debit/credit information on their website, they automatically deduct WITHOUT an OTP notification from your debit card which is a data concern and have to end relationship because of this, if you have prepaid electricity and make a payment with your debit card, eskom doesn't deduct from debit card simply because it is a prepaid service. you don't pay.. then you don't get service.