Very likely a scam. They repeatedly asked me to provide my address or last 4 digits of SSN, but refused to say what the call was for and said "This isn't a sales call." and "It's about a very important issue".
They wanted me to *verify* my mailing address, but wouldn't tell me who they were calling from. Just said it was "important, time sensitive information" -- Told them I'd wait for any mail they'd like to send to me.
No message left. Called back and the person tried to get me to give her my name and information. I told them to stop calling me. She kept asking for my name.
Very likely a scam. They repeatedly asked me to provide my address or last 4 digits of SSN, but refused to say what the call was for and said "This isn't a sales call." and "It's about a very important issue".