call from allied interstate?

I just got a call from "allied interstate" asking for my husbands ex-girlfriend with whom he has a child with. Please let me know how they would have got my number nad why they would call me. thank you.

They collection agency is skiptracing.....trying to locate your husbands ex. Nothing illegal about it. How they got your number? There are lots of ways and services they subscribe to...again nothing illegal. Pass the message on.