called but no message.  hung up after answering

Called and asked for someone, but refused to give their name.  Only said he was "Community Service."  When I refused to give my name, he sad, "well Good Morning" and hung up. Very sketchy.

Blank call.
When I called back, got "whata  wonderful World" for a few minutes
gave up after that

called and they hung up. When I called the number back I got a message that they are calling for the national cancer coallition and will call back to try and reach me. Also that they are registered with the state. Customer service # on the message stated 800-891-1430 option 9 adds you to their do not call list but your number can not be blocked in any way and you have to call from the number you want on their list.