No Internet connection

This company seems unable to fix/provide me with internet connectivity. The speed of the line testing between 40 and 50mbps, although I pay for 100mbps but this is not the main concern. I get connectivity but no internet, so the line is useless. I have been complaining for weeks now and all I get is a call telling me they did some adjustments on their side, it should be fine now which never is. Never once did they visit my house to solve the problem. Herotel is useless.