I have just had that exact problem except I had timeouts when browsing so bad I didnt even bother. I did this.
1) Spoke to my isp so that I could tell telkom that
2) Told telkom I was experianing packet loss and websites were timing out
3) Told telkom I had tried multiple routers and different internet service providers
I advise calling mid evening, tend to get the best people at that time. Two days later it was fixed without them being able to give me a concrete reason.