MTN overcharge of R10000 over 2 months

MTN has billed my cell account for a data bundle for 2 months but did not load the data bundle. They then charged out of bundle rates for the data used. The overcharge on two months bills is approx. R10 000. I have been trying to sort this out for about 6 weeks. I was told charges were correct. Have been trying for nearly a month to get itemized billing and data validation reports. Finally received one that proves no data was loaded but was charged for. Now I have to wait while they try to sort out. Really. MTNs customer service department does not work. Very unhappy and thinking of taking cell c up on their offer. Cant be much worse can it?????