Our phone system is currently down. Our provider, BT, don't seem know what the problem is. So far they've just told us to reboot our firewall and reboot our phone system. Suspiciously, we are also have problems connecting to a few websites, although the vast majority are fine. I've done a tracert on one of them and the results are:

The first IP is our firewall, the second one is our public IP address and the ones after that are BT servers. Does the fact that it gets as far as BT's servers suggest that the problem is at their end rather than ours, or is there anything at our end that could cause these issues? I can ping the IP address via external tools like http://tools.pingdom.com/ping/?target=54.76.183.250&o=1 so I know that the websites in question are ok.
I know next to nothing about networks, so any advice would be much appreciated. If I can establish that there is a problem with BT's servers, then I can assume that the problem we are having with our phone system is likely to be connected.
So, is tracert telling me anything useful?