Sky broadband _ had 3x visits with no installation, what do we do?

My husband signed for sky broadband + TV + Streaming for that deal they have.

We received everything but the thecnitians came to install the broadband (we ordered higher speed and our current broadband is with Virgin media plan).

The thing is, we have had 3 visits and we are waiting for it for 2 months now, everytime they come they give the same lame excuse: "there's no signal coming through the line, so it's broken somewhere in the neighborhood and it will take 2 weeks for us to be able to install"

I tried calling but to no avail.

Any advice, is there a regulatory service where I can complain?