Paying for a unreliable service.

I recently got internet installed at home and for the past 2 months I’ve made several complaints about the line speed being terrible. I’m paying for a 4 meg line and I do understand that it will fluctuate at times but I’ve done numerous speed test and 90% of the time I am running less then 2 megs. I sometimes run as slow as 0,3 megs. I’m considering canceling my contract but at the same time I don’t want to have the penalty fees and bad credit that I’ve read some clients of Telkom have received. What are my options going forward?