[otrs]Ticket vanished?

We’re running OTRS Community edition I have a long running ticket (which has been closed about 3 times, then reopened because the person keeps replying to the email with the ticket ID that seems to have simply disappeared from the system. I got a question from the person yesterday, wrote the answer, and went to revisit it this morning and the ticket is just gone. I cannot find it via search. What should my next steps be? -- Bruce Johnson University of Arizona College of Pharmacy Information Technology Group Institutions do not have opinions, merely customs