Transferring a cancelled contract from Autopage

I'm really disappointed with the way in which MTN has dealt with my contract transfer from Autopage. My two year contract ended on the 11th of March, and I asked that the contract be cancelled and I be transferred to prepaid. I received an email from Autopage stating that I would be transferred to prepaid on the 14th of March. I was shocked to find that my R385 balance had been wiped out to about R1.64 on the 14th of March. Further to this, I have received a bill from MTN for R218 this week, when I was under the impression that I am on prepaid. When I queried this with MTN, I was told that my contract was never cancelled, and that it would take a month to cancel once I have presented my ID. The lady at your Sandton City branch was apathetic to my cause and simply said that she has to query this with Autopage who are now impossible to contact. I feel like this is pathetic service from MTN, who are simply demanding payments from me, yet are offering little service. In addition to this, if I am still under a contract service, why have I not received any airtime for the 17th of this month?