MTNMONDO please stop debiting my account!!

Suddenly I have a debit order coming off my account of R149. I have no dealings with MTN and I have never agreed to any deal whatsoever!!! Its very annoying then going to Clearwater Mall only to be told I must go the Southgate to fix the problem ? Why is this MTNMONDO debiting my account? I want the recording where I agreed to this!