loss of terestrial channels

Hi guys I am currently losing all bbc itv channel 4 and channel5 channels can anyone tell me if they are experiencing this or is this something to do with a server problem totally baffled by this one
I am getting all pay per view channels so really baffled
cheers Tonyd

What receiver and image are you using? Where are you located?

If you perform a scan, how many channels do you pickup?

Also, please note that terrestrial channels are only available via aerial and not dish. I understand you mean to say free to air channels.