Forever locked iPhone 12 Mini to Virgin Mobile?

Hello! Not sure where else to post this or if anyone else has had a similar issue.

We bought an iPhone 12 Mini for my sister off of Kijiji in Toronto, Canada. The person said it was unlocked with Virgin Mobile. Tested SIM card and IMEI and all good. Now when we put in my sister’s SIM card with a different carrier, it says “SIM not supported” and called Virgin Mobile and they said the account is locked due to fraud. I’ve tested the IMEI since and it still is clean.

The person I bought it from won’t return my calls and now my messages won’t go through. I’m assuming I’ve been blocked.

Virgin Mobile says the only option (if we want) is to contact police to try and find the person, but not much else to do.

Is there really nothing else we can do?? Sadly, I’m thinking we’ve just been scammed and there’s nothing else to do, can anyone help or suggest anything?