I bought a car from a private seller in the US. To guarantee the availability of funds I issued a cashier's check to him. My banks account shows a withdrawal of the correct amount on the date that I issued the check. He claims that he deposited it two weeks ago and it still hasn't cleared. He claims that his bank reports the "limbo" status of the check as being because "the funds are not authorized for release". I called my bank to follow up on the status of the check but they claim they have no information about the check (whether it was deposited, cleared, or other).
Is there anything he or I can do to get more definitive status about the nature of the check?