you want to report an IP "attack" what do you mean exactly?
If you're saying that your firewall has reported an external attempt to access your machine I'm not surprised that BT aren't interested. It happens thousands of times a day, and there's nothing they can do about it. The fact that the "attack" appears to come via the BT servers isn't in itself surprising either.
My advice is that unless you have suffered as a result of this incident you should forget it. It's a common occurrence, and part of Internet life.