My MIL called me about something like this a few months ago, said she got a call from someone saying that she had $1,500 coming her way from overpaid taxes or something like that. I told her that it was 100% a scam, that the caller was just trying to get her personal info to steal her identity. She said after the phone call she got an email with a link to complete a form on the state website, and I told her it was probably a phishing site which installed some malware on her PC while she was on it. I had her send me the email she received and I checked it out, and it looked legit. It linked straight to the official state website, not a spoofed page or anything like that. And sure enough, a few weeks later she got a check in the mail for the exact amount she was promised! Even then I was skeptical, I told her I bet it's fake and when you deposit the check it will bounce, and when you call in they'll ask for your bank information so they can do a direct transfer, and that's where the scammer takes all your money. But nope! Check cleared, money was in her account, not a scam at all.
So I went on the site and found out I have $350 owed to me, my check should be here soon!