A breakdown at all levels

I was a Nashua Mobile contract customer for over 10 years. MTN took over NM last year and this is when my troubles began. They reduced my credit limit to R280 (from R1000) without consultation which resulted in me running out of airtime halfway through the month. I tried calling the callcentre and now have the MTN tune branded on my memory. Resorting to email meant be passed around the entire organisation like a ping-pong ball. I eventually muscled a R30 increase in my air time limit despite telling them that I am earning over R1m per year and am private banking client with a spotless credit record. I forged on and decided to hold on for the call centre for 20 minutes and eventually spoke to Gillian who offered to pass me around the whole organisation once more. To add insult to injury, they cut me off as I was waiting for a reference number as my time-limit was reached. No call-backs, no reference number and all aI want is to cancel my contract and get away from this useless organisation for ever. Oh - don't let them convince you to change to LTE if you are in the EC - I use Edge most of the time