Under Reports run the Participation Detailed Report and reverse sort on the Status column (click the column header twice). You'll find the members who made selections up top, whether finalized or not.
Next, enter into the member selections (from Comsend, no need to enter via Purim Project), select Current Selection from the drop-down and remove all selections and Finalize. You may find there are no selections as the member may have signed in and didn't make any. But if the Finalize button appears up right then you should finalize as the member may have previously finalized selections, entered again and removed them but never finalized the removal.
You can also see actual results of the finalized selections under Reports, Detailed Invoice report.