855-659-3371

Says it’s KPHLaw

This number keeps calling me, when i Google it no business comes up. So I don't answer, don't trust their voice mails either

No idea who this is. If they really wanted to get in touch they would have a real person rather than an automated message - especially if it's a legitimate law office

This number is relentless with calling me. The VM asks me to call back and quotes a case number. I have no idea what this could be but the fact that it’s so relentless makes me worry it’s legit.

Well, they are "relentless" because they want to scare you into paying them.  From what other posters have said on this site this is not actually a law firm.  I would be willing to bet that you could easily check that out.  I would also be willing to bet that you can easily check out the debt collection laws in your Province if you had taken the time to do so.

If a legit company calls they have a person make the call. I don't participate with any entity that uses Robo calls.
Scam

What was the message the "Robo call" left and why didn't you put that in your post?

Caller ID shows Department of Defense but when I look it up it shows some law firm