Bamboozled into a migration of my current MTN contract without explaining the costs involved.

I was telephonically contacted by a salesperson from MTN while driving. He convinced me that they were offering me a better package. I was not aware that it was a migration and that it would cost me nearly double per month. As I have a hearing disability and was not wearing my hearing aid at that moment, what I heard sounded reasonable. Only after I received my following statement, did I realise that my monthly premium was more than double. Being a pensioner, this is totally unacceptable. I visited both Bethlehem and Bloemfontein MTN branches and e-mailed the head office, but to no avail. They are of the opinion that I agreed to the migration as they have it on a voice recording and that is the bottom line.