Data (cases) missing after synchronized

after completion of survey, Tab shown data synchronized successfully with server. But, when download the data file some cases are missing. I think data was not synchronized. How to identify those data or how do I get those cases? Please help me.

Pramodcon,

find the interview key in the interviewer actions log
https://support.mysurvey.solutions/headquarters/reporting/detailed-action-log/

then write to support with the name of the server, interviewer, questionnaire, interview key and the date it was synched.

Best, Sergiy