Why pay for no service

[Mimij80]

For over 3 weeks have had intermitent broadband.
What I want to know is why am I paying full price for a service, when not receiving it.

They think a few gigs on my mobile is gonna work, but when you rely on broadband for work and home, a few gigs on an occasional mobile (which also does not get full coverage) does not help.
Had anyone else experienced this and how did you resolve the issue? 

[GD1]

@Mimij80  What have Sky said about the issues when you reported it to them.

Withholding payment is the worse course of action to take in this scenario.

[Mimij80]

I'm not withholding payment. It was the whole area affected. Many of my neighbours were experiencing the same problem. 
I was looking at the update on the system and it kept saying 72 hours it would be fixed... it weren't.