Unknown, leaves no message.

Missed call.  No message left.
Dial number and you get a 10 second time delay and then a busy signal.
Blocked caller

I answered it, its just a recording,  they tell you something about your warranty expiring and want to know you want to talk to a specialist concerning it.  I said yes and immediately regretted it.   When you say yes and they record that yes, its as if you've opted in.   So now they have my yes recording to sell to other people.  I expect I'll be getting a lot of future calls from people that who believe I was seeking them out, I also demonstrated I had a valid number..   I noticed on the next question they asked me, that they really didn't know who they was calling.   Its a spam call.

Called 7:30a on cell phone! Ignored and blocked.

No one spoke.