Sometimes a questionnaire that are in the status of incomplete/complete disappear on a tablet. The interviewer have to uninstall and reinstall the application and after that the questionnaire will appear again.
This is a known issue as described here.
To my knowledge, uninstalling the application will erase all data that was captured and should therefore be avoided by all means!
The interviewer app does not separately visualize the questionnaires, which do not have statuses. @amarone most likely meant interviews instead.
If the recommendations in Peter’s email are ineffective, provide more details, please.