Missing Channels - How do you find out of it's a line issue or something else?

I've noticed today that a few channels just display a black screen while others are working fine. For example, my Sky Sports and Movie channels are all working fine, no issues, but channels like Good Food and QVC to name just a few aren't working, I just get a black screen. While other channels start OK but then freeze.

If channels like Sky Sports and Movies are working it makes me think it can't be my line. I've also had two lines at the same time (24hr test line alongside my usual line) and I still get the same issues.

How do I find out what is at fault here and how do I go about fixing the issue. The wife needs her cookery programs! Help!
 
Yeah, it was all going fine until monday/tuesday. both boxes here lost all channels and slowly came back but everything i have now was back up yesterday but still missing some channels like deja-vu, encore and couple of others.
 
Back
Top