Rang the phone 2x and hung up, probably a con.

I've received calls from this number and no one answers when I pick up the call.

These [***] keep calling me. I reported them to FBI

Yep... offers to send me a $100 gift card, but I have to give them my credit card number to pay for a $4.95 shipping fee.

Advance Fee Fraud Scam

Haha.

Caller ID: South San Francisco Bay Area.  I called back, the recording said:
"Hi this is Lisa with Reward Redemption.  You recently visited one of our affiliate websites."
There is an offer to win a $100 rebate card.  
Oooooooo, a "Reward Card"!   NOT a gift card.  Big difference.  
Either way, block the number.