Sorry to give you an answer that isn't an answer, but honestly who is in the right may require litigation to figure out. Simply listing a student loan on Schedule F of a discharged bankruptcy case does not normally discharge the student loan unless the student loan is of a nature which was dischargeable without an adversary proceeding.
1999 bankruptcy cases were under the old bankruptcy law, which was a little more lenient in what student loans were discharged than the new law which became effective October 17, 2005.
Generally, under the old law if a student loan was a private loan which was not government backed and which was not made by a public institution (basically) then it would often be discharged withot requiring an adversary proceeding. If it was a government or government-backed loan or made by a public institution, then the debtor usually had to file an adversary proceeding to try to get the loan discharged by showing that repayment of the loan caused an undue hardship on the debor or debtor's dependent, which was a pretty tough thing for the debtor to show normally. Unfortunalte,y even under the old law there was a pesky sentence at the end that was sort of vague and some student loan lenders said protected even private loans. I'm not sue case law supported this assertion, but that was the argument.
So, you may want to check the fine print of your loan agreement to see if it was government guaranteed, etc. I had a case very similar to this where an old student loan lender popped up after discharge and wanted paid. I said it was a private loan, and they said even though it was a private loan their position was that the broad language of even the old bankruptcy law still protected them. Facts were pretty uncertain, so we settled for half to keep both sides from having to spend attorneys fees to litigate it and potentially lose.
I'm not saying this resolution is appropriate for your situation, but you might want to talk to your bankruptcy attorney and see about getting it resolved. Your attorney may be able to reopen the bankruptcy case and file a motion for contempt against them if the loan was discharged, or your attorney may review the documents and tell you you'll lose and to pay it, or maybe you can settle for some amount in the middle that both parties are happy with.
I hope this helps and a positive feedback is always appreciated if this was useful to you.
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