Vodacom internet not barely working

I have two Vodacom router at my home that I use for work and the last 3 months my signal has gone down tremendously. I use to have 20mb download speed at my house and now I don't even get 2mb download speed and that is if it is running.

I called Vodacom to help resolve the issue and they use the same excuse that everyone is having the same problem. They said that Vodacom has installed fiber in my area and that I can install that to have better signal. I said that it is fine if they cancel my modems contract then I will take the fiber but they said I can not do that without paying penalties.

Why should I pay for a service that I am not receiving? Most off the day I can't even open my email!