Mtn
Abnormal And Unkown Billing

I'm having an account for broad-band with Mtn which bill me R329.I was billed R810, R920 and R910 in three consequitive month. I phoned head office to cancel the subscription that they claiming Im subscribed to but they failed to do so. And the Broadband its suppose to be on top up according to our agreement. Please help regarding this matte