A friend of mine had a similar problem
His internet wasn't working but the sync light on the router was flashing and sky charged him for a new router and that didn't work either.
It took Sky 2 months to track down the issue that they had switched his internet connection off for non payment as they took down wrong details for his Direct Debit when he switched banks.
AMD FX-4100 X4, MSI 990FXA-GD80, 16GB DDR 3 Cosair Vengence 1600Mhz, 9351.1GB Hard Disk Space, 2GB ATI 6670 HD PCI-E 16x Graphics, 850watt PSU.
Ex AOL Dialup 56k Customer....
Ex Freedom2Surf 512k and Ex Eclipse Internet 2mb Customer.
Virgin Media 120mb Cable.
Virgin Media R EVIL!!!
http://www.speedtest.net/result/2943275661.png