Broadband connection

[lasfur]

I have for the last week been unable to connect to the internet via my broadband, but Ok through pay as you go with Wanadoo.
I have however noticed by accident that I can connect to the Internet via broadband if I make a call on my home phone or phone home from my mobile, it seems that I can only connect to the internet through Broadband when the telephone line is activated. Unfortunately this only last for as long as I am on the phone, if I put the receiver down, the ADSL light on the Router goes out after 3 minutes and I lose connection. Your help would be very much appreciated