Incompetence

I cancelled my month to month contract at the Maponya branch. They told me that they will cancel it on my behalf. I left the router with them as per their process. Mtn debited my account again and invoiced me saying that I used 15 gigs. I don't even have the router. I went back to Mtn but got no help, just excuses. I have been calling Mtn but nothing. This is horrible service.