NO CREDIT REFLECTED AS PROMISED

I WANTED TO CHANGE MY CONTRACT TO PREPAID AFTER IT WAS FINISHED (THIS NUMBER ***) A CONSULTANT CALLED TO BEG ME NOT TO GO PREPAID AND TO CONSIDER TAKING OUT ANOTHER CONTRACT AND AS PROMISED I WILL GET 3 MONTHS FREE SUBSCIPTION AS WELL AS ONCE OFF CONNECTION FEES WILL BE CREDITED TO MY ACCOUNT OF ABOUT R510.00 I DID THE UPGRADE ON THE CONTRACT AND I AM STILL YET TO RECEIVE THE CREDIT ON MY ACCOUNT AS PER FEBRUARY INVOICE NO CREDIT IS SHOWING. IF THIS IS THE CASE AND MTN CANT UPHOLD THEIR SIDE OF THE DEAL I WOULD RATHER GO BACK TO PREPAID THAN DEAL WITH MTN POOR SERVICE AS USUAL. YOU QUICK TO OFFER FREE SUBSCRIPTION BUT NOT QUICK TO PUT IT IN PLACE.ALWAYS EMPTY PROMISES AS USUAL.I EVEN RECEIVED A REFERENCE NUMBER (***) AND HAVE CONTACTED CUSTOMER CARE AND STILL NOTHING. SINCE THE 10 FEBRUARY I HAVE HAD NO FEEDBACK WITH REGARDS TO THIS AND I DONT FEEL LIKE SITTING ON THE PHONE FOR 20MIN LISTENING TO THE STUPID MTN TUNE AND FOR MY CALL TO BE DROPPED EACH TIME. PLEASE SORT MY CREDIT OUT OR CHANGE MY SIM TO PREPAID AS PER MY ORIGINAL REQUEST.