Bankruptcy Law Questions? Ask a Bankruptcy Lawyer.
If the loan is discharged, you do not owe them money, period. If they didn't come pick up the car that is their mistake, not yours. Without the title you would not be able to sell it, so you could either keep it and when it is just junk sell it to a "junk car" guy (the guys who buy cars for 100.00 for parts, even if there is no title), or you could put in for a "lost title" replacement. If you get the title, then sell it.
You do not owe anything for this car, your only issue now is the title. Of course you could always ask them to come get the car, but if they haven't they probably don't want it at this point. If anyone gives you trouble in the future about the loan, simply tell them it was discharged in bankruptcy and provide the filing number etc.
Let me know if you have any more questions regarding this.