4mb line speed dropped to 3mb line without consent

I have an uncapped 4mb account with Telkom for the last 3 to 4 years now.<br> Over the last year I have noticed that my line speeds keep dropping in 512mb increments.<br> I called telkom about 3 months ago and queried why my line speed had dropped from 4 mb to 3 and a half meg, where the operator responded that my area can only handle 3 and a half meg line speeds, where i rep**** that i have been on 4mb for over 2 years and that my area can handle 4mb. with a bit of arguing she refused to increase the line speed and eventually cut the line. I tried for 3 days to get hold of Telkom to stop my account with them and have been unable to do so since. I have just come back of holiday now and have noticed that my line speed is now only connecting at 3mb. I am again going to try cancel my account with Telkom, but i feel more action is needed here as I am paying full price for a 4mb line and uncapped service, But i am only getting 3mb which to me is blatant theft. Telkom should be sued for this as this is a case of if you don't like what we are doing go somewhere else and they know they can monopolize this are as the Secunda area suffers with proper internet connectivity options.