MTN have proved to be the worst. HereA AAas why

I have lodged numerous requests for a refund R2267.72 which you owe me due to overbilling and have received numerous responses with promises of a refund but no action and a stupid responses stating that I am on a data plan which is not applicable to me. ***; REQ:***; REQ:***; REQ:***; REQ:***: REQ:***; ref ***7. THE LIST GOES ON!!!!! Last response from Tim on 27 Jan as follows: We have also now requested our Banking Department to credit the amount of R859.20 to your banking account but I have still not received a F'en refund! Due to your pathetic service, I called the call 808 call centre to request that 2 of my contacts which have expired not be renewed be migrated to prepaid. Kevin Foster from you retentions department (ref ***7) even emailed me to confirm the migration but you have not implemented the migration and continue to charge me. Your system and staff f up should not be the customers problem