Car Was Stolen And Involved In An Accident. Now I'm Being Told I Owe $5000.

Long story short, around a year ago my car was stolen overnight and I found out the day after, filed the police report, notified my insurance company at the time and filed a claim for it. The car was recovered about 2 days after that, but it was left behind, wrecked and apparently previously involved in a hit and run according to the recovery officer. I only had liability coverage at the time so I ended up losing the entire car for nothing. But the insurance did close the claim as no one was found to be at fault for the hit and run incident.

Fast forward a couple of weeks ago, I got a letter from Subroiq in the mail claiming that I'm liable for $5000 and that they would get my license suspended. And agent of theirs also contacted me on the phone after, claiming because I only had liability, that's not "full coverage" and not comprehension so I am still liable for the amount. Which did not sound right to me. He asked for the police report, which I have since provided. He also claimed that the adjuster of my claim said they denied coverage because I didn't have insurance at the time. But that's not what my adjuster told me, my car was stolen, no one was found at fault and so they closed the claim.

Am I actually liable for anything here and what should I do next? As the Suboriq agent insisted that they will get my license suspended if I don't pay the $5000.

Edit: The letter/collection is regarding the vehicle that was in the hit and run. My stolen car was fully paid/owned by me at the time

Location: Las Vegas Nevada