At my wits end

I am at my wits end with MTN. After being their loyal customer since the last century I have in the past few months been met with a litany of obscenely inferior service. 1. I queried my data charges last year a number of times. No response. My data charges are over R1000 per month. As I use wifi and buy the data bundles that seems strange but despite repeated requests - including going into MTN personally - I am being ignored. 2. I have a content charge on my phone as somehow - not willingly - I have something installed. I called in 2 months ago (after the sms number wouldn't work). After 45 minutes on the phone I was assured that it would be removed and that there would be no charges. Month after month I am now being charged for this *******. I don't even know what it is! My emails have simply been ignored. 3. Last week MTN debited me more than double my account due. I had to call and threaten to lay a charge of theft before they refunded me. My husband is trying to persuade me to migrate to Vodacom. At this stage when I can't even get any responses to my queries never mind service I think that is probably my only solution.