They appear to be some kind of debt collector, but they didn't identify which one

Got a call from this number asking for my husband and wanting me to verify my husbands last four of Social. I did not give her that info, she wouldn't tell me what it was regarding, just said it was a business matter! I'm not stupid.
She gave me a number for him to call.
877-946-1753

Bill collector trying to collect a debt that is past statute of limitation. 12 years old. Say that can't take legal action but it's "the right thing to do".  Hung up on them