Unable to resolve technical issue

So recently I upgraded my ADSL account with a telkom special to the 4MEG Uncapped ADSL for R599 per month. After 2 days they said the upgrade was successful. I ran a speed test and hardly even got 1MEG. I logged a technical fault. They checked and after 2 days said there was nothing wrong. I then called and logged a new fault with them. They had me on hold for over 2 hours before answering, finally they did, they said there was a fault and they would resolve. The informed me a few days later that the fault had been resolved. Again I ran another speedtest, I know get 1.2 to 1.5 MEGS as a download speed, Telkom where is my 4MEG line I am paying for??? I should at lease be getting download speeds of 3.4 to 3.6 MEGS???