Agree, Surveyor, The first thing you could do in these circumstances is to comment on the changeset(s) themselves. Ask for the source , any further details and prompt them in the direction of the two extracts above and ask if they could consider reverting. If you don't get a response back in say about 3 days, you can revert the changeset using a JOSM plug-in called reverter or in this case, manually. 