Called me on my mobile number. Did not leave a message.

I received a voicemail from an Officer Paul Martin who didn't identify where he was calling from and stated that I needed to call him immediately as this was an urgent business matter.

I got the same message it seems. But he sounded like a robot and wanted my "Attorney of record" or me to call back.

I got the same message from an Officer Mike Brown, wierd accent.  Thinking its a scam.

Yep, it's a scam.  Legitimate debt collectors know that it's illegal to pretend to be law enforcement.  Only scammers try that intimidation stuff.  Read what the FTC says about identifying fake debt collectors:
https://www.consumer.ftc.gov/articles/0258-fake-debt-collectors