Change in ongoing survey - data recovery

You can also restore the last version (which contain that question) from Tools-->verions-->view verion histore. And if both the above options dsnt work, then Qualtrics Support team and they must have some backup plan for your data.

better not delete the question insted hide it by putting in false condition (condition that never satisfy) doing this data collected for already completed responses will not lost.

No... unless Qualtrics store it somewhere

@YASH1T thank you! this saved my survey responses.