Double charge in Dec 2023 and they cannot resolve why even though i had sent my bank statements to show all my payments.

in December 2023 my montly bill was double and i only paid my normal monthly i went to the Norkem Mall branch to enquire to todate i still encounter messages that i owe then R1685. i provided the branc with statement to show my payments made monthly. on the 9th Feb the matter was escalted but still nothing on the 19 Feb my services we disconnected i went to the branch. they made calls the matter escalated nothing. note in december 2022 i was charged double and i paid but this one i did not i wanted to understand what month did i not pay. because if you short paid your services get disconnected for a R45 short paid.