I receive a call from this number at least once a week. They never leave a message. I'm half tempted to actually answer next time, just to figure out who they are and why they're calling.
Appeared on my cell, which doesn't let unknown numbers use the ringer, so I had not heard it. I usually keep the cell offline, but turn it online, when I drive some errands. The call had arrived during that trip. Blocked now.