I tracked down these numbers: (202) 224-3121 1 866 220 0044 (worked as of this afternoon!)
I was told that the govt has never had a toll free number, and that any toll free number you find is paid for by a PAC which forwards the call to the Capitol Hill switchboard. So the switchboard has no way of knowing your number when you call them using the toll free number.
I called the toll number asking for another number in case that one was busy, and was told that "this number is never busy". I thought, we'll see about that!
That is the number that was given in the email sent in the email promoting the event. In fact, I just copied and pasted the email into Word and deleted some things. It would be extremely aggravating if you are correct, as I am sure you are, for two reasons. 1. I have already had a few hundred printed. 2. I was going to use the 202 number but thought "Well, this number came from ETF HQ so I will go with it." I'll have to double check it.
I just called the number on the flyer and it does take you straight to the Congressional Switchboard. They connected me straight away to my Congressmans office. The person on the line said she had already received many calls. She said she thought it was a good idea and the office would be sending me a reply.