DEBIT ORDER ERROR SINCE NOVEMBER 2014

i have been a loyal MTN customer for many years. I have 4 contracts currently with MTN & I am paying close to R1400 p/m and since November when MTN's debit order failed to come off my account for whatever reason i have been struggling to get my billing corrected. I had called 808 when i first realised my debit order did not go off and i had plenty of funds in my account. Since then i have spoken to countless agents who know nothing and promised to call me back but nothing. last call was this month a few days ago and still waiting for a call. I asked for this to be escalated to management but nothing. I have been told that i am a month in arrears. how is that possible when i have a debit order in place, never missed a payment till now and even volunteered to send my bank statement showing that i had funds. now i am accumulating interest on this arrears which i refuse to pay until i get some sort of explanation on what happened. I have asked the agents to bring out the recorded calls but to no avail. last spoke to bonngani who assured he would geta supervisor to call me but nothing. I am going to blast this all over social media and cancel my contracts. Pathetic service.