If they are legitimate, they are not allowed to call other people and disclose that you have a debt.  If they are legitimate, they are also required to send you a verification of debt showing the amount owed, who the original creditor is among other things.  (Fair Debt Collection Practices Act).  If you ARE served with papers via your local sheriff's dept, you must show up at the hearing, even if you can't afford a lawyer, otherwise a judgment will be granted against you to said legitimate company.  Any time someone calls about a supposed debt you owe - THEY must document via snail mail - NOT email - what you owe.  I could go on, but I know that Resident47 and others have posted what you should do in these cases many times.  If the debt is legitimate, then yes, address it while you can.  But always demand proof.  There are many companies out there who can and do skirt the legally required steps, but they can be fined heavily for doing so.