Endless problem they don't solve or get back to you

I have laid my 3rd complaint now on here..Telkom Greenstone opened the incorrect contract on my name(more expensive,bigger one)..I have now been charged the 5th month for a contract I did not want and I have been personally contacted by the store owner/manager and he just tells me he is out of office and going to head office constantly and that he is sorry..this is endless I simply wanted them to change it to what I wanted and be refunded the overcharge..now I want to cancel this is utterly pathetic..no idea about customer service..just because they respond doesn't mean the problem is solved .. ***