My dad passed away 4 years ago, and we (my sister and I) have received calls from an unknown number. Today we got a message asking us to call back. My sister called back and it turns out it's a debt collectors agency and they didn't know my dad died. We had no idea he was in any sort of debt but they have requested proof of his death. What do we do? We don't even know if it's a scam or legit. Panthera Finance is the name, are they to be trusted?