They are entitled to one call to locate you. They can legally call a spouse or a parent of a minor child and discuss the debt. I think. Although that makes no sense, since minors cannot enter into contracts unless it is for food, shelter, clothing, or medical care. You go read the FDCPA and see what you think.
They did not say why they called because the FDCPA says they can't unless they are talking to you. You need to find out if this is for the same debt or a different one.