MTN

I have a contract with Mtn. I have changed dates so they debit on the 25th of each month, when the day has arrived they don’t debit when I check my app I don’t have where it shows debit failed. I even went to Capitec to check if maybe there’s anything wrong they said my bank is ok. I have been calling them to fix the matter for the 5th time. What surprises me they always telling me their debit is always declining but when they have to double debit me it does not decline why? I’m so irritated, mad and everything. Please help me with the matter Peter. They enjoy double debits and people being in areas, I’m honestly tired of this because I repeat myself to Mtn customer service agents every month. I don’t know what to do now.