It is a medical debt for my son's treatment one year ago, a sum of 6 bills from the same provider. I've never had the bills, the provider billed my ex husband (my son's father). Our son is on his father's health insurance, and per our divorce decree the father is also supposed to pay uncovered med. expenses (which he refuses to do). So, the hospital sent all bills to the father directly, I've never received anything, never had phone calls about this debt, nothing until yesterday I received a letter from a debt collector. What do I do now? Call the collector? Write them and request "validation" - what is it? Can they report it to the credit bureaus? Can they sue me for a debt, that's never been in my name to start with?