Not even an MTN customer but my account keeps getting debited!

I am not even an MTN customer in any shape, way or form but my bank account keeps getting debited by MTN for a product that is neither in my possession and/or do not make use of! I I have tried calling the 083 135 number for non-mtn customers but I met with limited self help options and speaking to an agent is not one of those options! I have emailed the *****s department but they keep referring me to calling the useless customer service number which does nothing!