Telkom not living up to their promises

I recently upgraded to a 10 Meg fiber line with a 50 gig cap.The only reason for the upgrade was based on the following.A Telkom representative assured me that the line will never go slower than 8 meg while within the 50 gig cap and never slower than 2 meg after the line gets capped.I was also told that network traffic doesn't have a significant impact on the speed.Now i am lucky if i get 6 meg while within the 50 gig cap and 0.3 meg after the line gets capped.After 3 days of phoning Telkom i realized that i am talking to a brick wall because i couldn't find a single person who could tell me why i am being **** to.Everybody i talked to was transferring my call to someone else and that went on for three days,so i tried to downgrade back to my 4 meg copper line.I was then told that i cant because there is a 24 month contract(news to me).I never knew that you can enter a contract over the phone.I believe that all the calls are recorded.The recording will proof my story.