I just found out that one of my phone lines had its long distance account terminated in January, and theoretically has had no long distance service since that date.
However, I've used it off and on for a few months now (it's a third phone line) and had no issues until a few days ago when it started getting intercepted with an announcement with an 800 number in it.
I wonder where the hell the billing records for this line went during that time….