1st ask the mapper in question (changeset comment) what their reason for the deletion was. We need to know if this was just an accident, or if there is a different reason.
2nd once that is clear you can try to revert yourself, you will need to install JOSM and the reverter plugin, and do a partial revert (as the additions seem to be OK). If you don’t want to try, I would suggest piping up here again.