MTN sim card blocked even though my debit order has gone off on time.

I have a contract with MTN and their service is absolutely terrible. My payment goes off via debit order every month. This month was no different except for the fact that my sim card ended up not working when i needed it the most. According to MTN my payment has not reflected and i'm in arrears however i showed the consultant at the store my statement and all she told me was to call 135 so i can fix the issue (MY SIM DOESNT WORK!!! HOW AM I SUPPOSED TO CALL ANYTHING) so i ended up stuck at the mall , unable to even request an uber for myself to go home. I then emailed them since i cant make any calls because they've essentially turnt off my sim card but still no response even after i sent them my statement with the debit order going off ON TIME. Im very disappointed in this company and if i could i'd cancel this contract immediately. WOULD NOT ADVISE ANYBODY TO ENTER INTO BUSINESS WITH THEM AT ALL.