Unknown Direct Debit

I am so disappointed with Mtn customer service,I called in to query about a direct debit of R212,66 that was taken out of my account which i do not know,called Mtn at Gateway mall some guy picked up whom refused to provide his name and asked if i had a contract so did advice that i have a wifi that i pay for on the 4th and asked how sure am I if it was not the same did tell him that the reference numbers are not the same and not the same amount he then advice i should call again and dropped the call