If an entity is listed on the creditor matrix in your chapter 7 discharge, and they are not exempt from discharge as a matter of law, then that debt is likely discharged.
But the other attorney is absolutely right. Your question is poorly phrased and it is not clear what you are asking.
If a debt is discharged, then the creditor cannot make a claim against you based on that debt. If the creditor was exempted from discharge by law, then they can sue you in state court, but not bankruptcy. If a creditor had and opportunity to object to or sue to determine the dischargeability of a debt you owed to them, but did not in the time allotted before your discharge was granted, then the debt should be deemed discharged. They may move to reopen your bankruptcy case and may move the court to allow them to file a late claim to determine the dischargeability of the debt, but courts aren't likely to grant that motion if they were properly listed with a valid mailing address.
Your post is not clear at all. You would get better answers if you simply told us what happened instead of us guessing who the creditor is, and what claim they may have. Most debts are discharged, but not all. Some creditors retain a lien, some many not. A creditor does not generally have to inform the Trustee of anything.
Taxes can be discharged if they are 3 years old, so 2009 taxes can be wiped out if you filed them on time in 2010 AND you wait until after 4/15/13 to file your BK. Yes, list your former landlord even if you think you do not owe anything. If each creditor is listed, you don't need to worry about a creditor selling your debt to a collection agency. Please hire a BK attorney.
Be sure to designate "best answer." If you live in Oregon, you may call me for more detailed advice, 503-650-9662. Please be aware that each answer on this website is based upon the facts, or lack thereof, provided in the question. To be sure you get complete and comprehensive answers, based upon the totality of your situation, contact a local attorney who specializes in the area of law that involves your legal problem. Diane L. Gruber has been practicing law in Oregon for 26 years, specializing in family law, bankruptcy, estate planning and probate. Note: Diane L. Gruber does not represent you until a written fee agreement has been signed by you and Diane L. Gruber, and the fee listed in the agreement has been paid.