Student Loan DOFD and collection questions

I had a call from a CA yesterday about something that I thought was history.

 

I had a PLUS student loan that was paid off 12 or 13 years ago. The final payment was about $6000.00, which I paid when I got a small inheritance. 

 

About a year after I paid it, I got a collection call, so I called the entity to whom I wrote the check. They asked me to sent a copy of the check, so I did. Anyway, after a while I never heard from them again, so I thought all was good.

 

Is there any glitch that would allow them to put this “defaulted” loan on my credit? I can’t even prove that it was reported late 12 years ago, therefore ineligible to go back on my report.

 

Also, I have no idea where that check is now, it was 12+ years ago! Can they garnish my wages?

 

Can someone kindly tell me exactly where I stand on this.