Not getting the speed I’m paying for!

I sent Telkom an email a week ago regarding my problem with my wi-fi, still havent heard anything. According to my statement I am paying for an 4mbps line, but I have 24 days worth of speedtest reports showing that I hardly ever have more than 1mbps. Sometimes 1.7mbps. This is really not worth it and I am currently searching for a different service provider.