1. Get an email or written communication from the bank of such a denial.
2. Get a copy of the check that was dishonored.
3. Find a local attorney who will represent a case for <$5,000 due to the bank's violations
b. Unlicensed Practice of Law (giving advice on what indorsement one should write OR what indorsement is acceptable as a non-party)
4. The bank will often just attempt to settle out of court for less + attorney fees. Accept this and an agreement that the bank will accept all future indorsements or face similar lawsuit.