Shocking Service!

I was overcharged by R225 and I called to find out why how it was calculated, I was told that there is a connection fee included which I was never told about and never agreed to when I app**** for the contract. I also haven’t received an invoice to date, even though MTN debited R525 from my account not R299 as agreed. I have been sent from pillar to post, I also sent an email but I haven’t received a response.