Refuse to migrate to pre-paid

My cell phone contract expired on 16 Dec 2015. I went to the Fourways branch on 17 Nov, to request a migration from contract to prepaid (observing a 1 month notice period).<br> <br> I have requested the same again on 17 Dec, 2 Jan, 5 Jan, 6 Jan, and 7 Jan, by going to the same branch, calling the call centre, and by e-mail, but I have received nothing but promises.<br> <br> After escalation, I received a mail from 'retention', asking me to reconsider - which is certainly not going to happen, after this experience.<br> <br> It seems as if MTN is either unable or unwilling to execute this instruction within a reasonable period.