Who called from 2067770966

This is a call from an environmental lobbyist group for donations.

Keep getting calls from this number, but they won't leave a message.

It is a call from environment Washington. You probably signed up with them some time ago and they are calling to get you to renew their membership.

Unknown caller always hangs up when I answer; calls only after 6pm and will call repeatedly in one evening.

Yes, this is a plea for donations. They are an environmental lobbyist group.