MTN incompetence

I received an email with an option (sim-only 1Gb data / 100 minutes airtime) to upgrade to, which I then did at a store the following day. However the store failed to do a proper job as the upgrade seemingly never happened. I signed a contract and received a copy on a stack of papers but when I received and sms to inform me of data and minutes loaded (start of new month), realised the contract was never upgraded!!! I then phoned MTN to attempt to correct it. After some gr8 effort on the line I finally spoke to a person that did the upgrade "properly" or so it seemed. However when I received my next sms to inform me of the data and minutes loaded on my number for the new month I realised that this time the contract was upgraded BUT did not the option I was offered re data and minutes, i.e. 1GB and 100 minutes!!! Since then I have attempted to contact MTN but with no success. I just cannot find a consultant or a "service champion" on a line as 135 is useless as far as that is concerned as you only speak to a voice and no person. HOW do I get MTN to correct this! It is total incompetence from MTN!!! I've mailed them .... NO RESPONSE from them!!