Unable to get help

I have an MTN router that is not working. i gather I have reached my credit limit - I do not know how, as I am told I have plenty of unused data. I have been unable to have the credit limit extended, to buy an additional bundle or resolve the problem in any way. I once managed, after trying for about 3 hours, to get hold of a person at the call centre who promised to increase my credit limit - this clearly did not happen. On Friday i went to the store in Sandton City. A very helpful consultant tried to get through from 3pm - many times. He managed finally to speak to someone at at 5.10 pm - to be told the financial department was now closed, and no-one else could help. I am now using a borrowed Vodacom device, and cannot wait for the chance to cancel my MTN contract. Never have I ever had such absolutely shocking service from ANY supplier.