....which makes me wonder how this can be done?
A phone number calls my line, and when you call back, you get a "not in service" message?

Yeah I got a call from this number tonight and I didn't answer it.  When I called back, it was not in service LOL.  Same as you guys.

this number called us on October 22, at 9:15 pm. I missed the call and they never left a message. Calling the # back we get 'not in service'

this is really werid,this number called me 12 times this morning sunday october 19th 2008one after another exactly 1 minute apart when i called it back of course it was a not in serive message and when i answered the 11th call ?it was a werid beeping sound... what am i suppose to thynk heere?i mean 12 times?common...

This call came in from someone supposedly representing TD Canada Trust asking who made the last transaction at the bank etc.
Obviously a scammer.

Caller from (613) 232-7437 said they were from OnSat calling on behalf of Bell Satellite, but then preceded to ask me if I had cable Tv or Bell Satellite..  I said, well if you are calling here on their behalf then shouldn't you know !!  I was then asked if I knew anyone, friends or family to refer to Bells services.  I said "NO", then they hung up...Scam artists!!