Telkom's 2 Meg ADSL Uncapped Line is very slow

I am with Telkom now for a number of years and I could not complaint about the service I received till 3 months ago. My 2 Meg uncapped ADSL line became extremely slow. Like 210Kbps download speed and 100Kbps upload speed with a ping of 909mS. A 800Mb file takes me 10 hours to download and then boms out in the middle. The Internet light on the ADSL modem keep on flashing and this is clearly a line fault. I reported it over and over but no-one from Telkom phone me back and nothing is done about my problem. Where I am paying for a 2Meg line Telkom is clearly in bridge of contract here and they are ignoring me.