Search by name and DOB and it will bring up addresses, phone numbers, etc. Every now and then, you can get people with the same name or a similar name with a similar DOB (same month and year for example). If whoever was filling in the details wasn't paying attention they could have easily put in the wrong persons contact info. They were probably just trying to find the most recent address to update what they had and messed up. Honestly, if you can get a human on the phone and walk them through why it's wrong, they should be able to fix it pretty easily. Better to fix it now before it gets sent to collections. The same database that gives them the addresses and phone numbers will also give them a SSN which will be wrong as well if they pull from the same record. That's the way it could get latched on to her credit down the road if it isn't resolved. You've got a while to get it sorted. I believe it's 8 months in collections before it affects credit. It's then up to 30 days for the credit to get fixed after the debt is eliminated.