Terrible customer service

Following the expiry of two of my contracts, I called the MTN call centre and requested the numbers be migrated to prepaid. I was told that the process will take a maximum of 24 hours. My request for migration was confirmed by an email to me from Kevin Foster of the MTN retentions department on the 12 of February (Ref Number: ***7). I did not use the sim cards since I requested the migration. On the 26th of February I found that the migration was still not been implemented and I email the retentions department. On the 15 of March Sylvia Makgopa from MTN Retentions responds to say the migration is being done, which is more than a month later than I requested. To make matters worse you have continued to charge me thus for totalling R370.07. I have emailed the retentions department for a refund but my emails have been ignored. I want a refund!