MTN Terrible Service and Poor Support

I'm am disappointed with MTN. I renewed my contact the beginning of the year. Now they have changed the minutes I get - 50% MTN network, 50% Other Networks. I use this phone for business. It has been 19 days and my any network minutes is depleted. This is effecting my business, as I can not contact clients etc = Loss of Income. I contacted the so called "Champion" Yesterday. He was so rude, basically he told me "What must he do about it?". I have emailed a complaint to MTN, with no response received. This is utterly disguising service from MTN.