Creditors who learn a debtor has passed away, need to file a claim against the estate, which may include a trust, according to the NWI Times in "Filing claims against a trust."
Filing a claim against a trust, can be even more complicated than filing against an estate, or maybe not.
It depends on the state. Every state has its own laws and procedures that need to be followed for a creditor to properly file a claim to receive the debt of a debtor who has passed away.
For this reason, it is extremely important for creditors to contact a local estate attorney to help them with the process. This is something that must be done without delay, since the statutes of limitations for these claims are often very short, again depending on the state.
An estate planning attorney can advise you on creating an estate plan that meets your unique circumstances, including addressing any debts left behind.
Reference: NWI Times (July 2, 2017) "Filing claims against a trust."