Caller ID: just the ph#-Seattle; no message=scammer

Caller ID: just the #; no message=scammer

Calls everyday.

Its some fundraising organization. They wouldn't state their name. They call me every morning at the same time and ask for me, and when told that I am not home and asked for their name, they hang up.

I am so tired and aggrivated with whom ever this person calling me.  It's almost every day and they as for the lady or man of the house.  I have an answer machine and i don't pick up until the party identifies itself.  What can i do to stop this?