Extremely dissatisfied customer

Every single month my mom's debit order goes off on the last day of the month to pay her cellphone bill and a few days later it gets suspended and every single month we have to call to tell your staff that the debit had gone off so please reconnect. Is there something wrong with your system? Why ask when we want to be debited if you going to suspend the account on whatever day your system reads that we should have paid it. I don't understand what's the problem🤬