MTN SUCKS!!! can't stand this network anymore

I had a contract with nashua mobile under mtn (before they sold all the networks to different service providers) which was due for termination in december but before my contract was moved to mtn I was offered an upgrade (by the nashua consultant named Jonathan) of the same package I was getting all along (R200 airtime, 25 sms's and BIS) exept the handset for R59p/m over 24 (sound clip available). This all happened in october 2014 then when all contracts where moved to mtn I got an email of the upgrade details with a different phone number from mine but other details were mine so I decided to call the mtn call cetre to investigate, I was given de run-arounds tranferred from 1 department to the other and then reassured that the upgrade didn't go through so I shudnt worry the only thing I needed to do was to terminate and change the contract to prepaid in december. Then december came and when I called in to do what I was told to do earlier on, to my greatest surprise I was upgraded for R350p/m with no handset and I apparently did it on the 12 of december but the person who assisted me is a ghost he/she is unknown. Now Mtn says I owe them R750??? 2nd contract 2nd bad service of mtn