If I receive a demand letter from a debtor or a trustee seeking the return of an alleged preferential payment or an alleged fraudulent conveyance, did I do something wrong?

In most instances, no. Preference and fraudulent conveyance claims are made by debtors and trustees in order to recover funds for the estate as a whole, and each has various potential defenses that may be asserted. If you receive a demand letter or a complaint, you should contact an experienced bankruptcy attorney immediately in order to avoid missing any potential deadlines.