Changing my line from a 4mbps to a 10mbps line without permission

In March i received a call from Telkom offering me a deal for a 10 for a 10mbps line and I decline by saying I'm not interested as I have a 4mbps and i even get the speed for a 4mbps yet, so why would I want a 10mbps is doesn't make sense. the next month i get my bill and to my surprise i was charged for a 10mbps line which i dont have. and now for the past few months I have been battling with telkom to give me a reason why they change my line from a 4mbps to a 10mbps line with out my permission, they couldn't answer me I have logged numerous calls to have this matter resolved but yet no results from. they are charging R800 for something i dont have, which is ridiculous. then i spoke to another sales consultant recently and she says i need to down grade my contract which i have been trying to yet for another two weeks... and yet again no surprise there Telkom call center agent Nosibusiso and Roxanne keeps telling me when i call after waiting on the line so long for an AGENT to help me just to say that their system if offline and that i must call back after 2 hours. which is pathetic, cause how can their service be down every time one call. They keen on charging for something you dont have, but when you want downgrade they not so keen to help you.

My opinion, Telkom is another one of those ***** company that doesn't deliver on service, the attitudes of their agents are pathetic and take people's money that doesn't belong to them. I want my money back and i want to down grade my service from a 10mbps back to the 4mbps that was Initially installed at my house.