Called during work hours. Left no message. Everything I found on the number said it was a scam, threatening legal action.

Call and no message why this they are calling.

Called. Left no message so I blocked them.

Offered a business opportunity.

with scam callers. You block a number and they call from another. DO NOT CALL LIST is a joke. They even have the audacity to call on holidays. Don't press 9, they are trying to see if they have reached an actual working #. They need to get a real job and stop harassing people.