ADSL line speeds

I am currently on the 2Mbps line however after conducting the line speed test it was noted that my line speed is only 0.3 Mbps. This has been a problem for the last three years however I have not received any help. I feel this is day light ******* as we are being charged incorrectly and Telkom has been charging me for the full line speed however my line speed is less than 10% of what was promised.