Subcribed to content Unknowingly

I noticed an escalation in the amount I was billed for my MTN Contract *** for the month of June 2015 from 500 to 1800 when I enquired at MTN they said they are investigating it will take them 21 working days to resolve the matter. For the month of July the amount further increased to R5800. I again logged a query with their call centre and found out my first complain was not logged so they told me it was going to take another 21 days to investigate. When they got back to me they told me I subscribed to Mira Net works of which I had no knowledge of. I want Mira Networks to refund me the money they have billed me from my cellphone contract for service I never subscribed to.