Currently answering on 1-866-537-8008
Their IVR system's a bit flakey. It now wants you to input the last 2 digits of your phone number before it lets you through and seems to just give up about half the time. Nevertheless, persistence pays off and it is possible to get through to them eventually.
Other known numbers;
18443074296
18338080051
18002709908
A couple of those sometimes pick up as some kind of book keeping scam.