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.
Changeset discussion comments can be more useful than private messages for a couple of reasons - one is that everything there is public, so everyone has an incentive to be extra descriptive and extra-polite. Also because everything’s public other people can see a mappers’ previous interaction with the community - often that allows a future commenter to give a bit of extra context to future remarks.