Overcharged

I signed up for a R999 contract for 24 months, for the first 2 months I was charged R999. Then in January they debited my for R1016 an extra R17 for itemised billing which I don't need and never asked for. It is an internet account what would I see? I contacted them via Facebook on February 11 and to date the guys on Facebook are promising that a billing consultant will call me but no one ever does. Tomorrow is Saturday and if no one calls me I am going to the bank and cancelling all debit orders because they are breaching the contract I signed. I signed a contract for R999/month not R1016/month. I want my money back.