Didn't answer but left no message.

Picked up, said hello and no reply.  

Did not answer but they didn't leave a message.

Answered call.  Immediately obvious it was a robo dialer.  Guy started off saying I hadn't extended the warranty on my car and started asking questions about the mileage.  I asked him who he was again (couldn't understand his response).  Told him I'd never done business with his company and didn't understand why he was calling.  He hung up on me.