They called at 3:30. As a rule, I do not answer any numbers that I do not recognize. This person did not leave a message. I think that there is a list that goes around that these [***] sell with your phone numbers. If I accidentally answer some of these spam calls it seems I get put back on the list as an active number and they call nonstop. I accidentally answered last week and now I've gotten 3 calls today and I haven't had any in months. From the comments this one sounds like they're confirming the names on their list and updating everyone who answers. Save the number as spam and program them to go to voicemail. That should hold them at bay for a while.
I received a call. I ignored it like I do every number I don't recognize. If it's important, they will leave a msg. I then blocked it.... simple... won't bug me again. :-)