If a claim is not showing up on the Appointments page, when you expect that it should, it usually means either:
The claim is not active. To remedy, make the claim active again: https://help.submitkit.co.nz/en/articles/9182418-how-do-i-make-a-claim-active-again
There is a duplicate of the patient in SubmitKit. To check, head to Patients, and search for the patient, if there is a duplicate, then merge them: https://help.submitkit.co.nz/en/articles/9158646-merge-patients