It *should* be fairly simple to just revert the situation to what it was before.
I've been suggested to take screenshots of the town size daily and use those as proof but in all honesty that is nowhere near being acceptable.
There isn't just one person handling the whole town in most cases and it would become nearly impossible to compare data that way due to different time schedules/zones.
Since this could happen again after a fix if nothing changes in the system, it would be better to have a way to rollback chunks claims (and only _claims_) and avoid losing progress considering the amount of time needed to plan and build a town.
As a non written rule we decided to mark Dracomere's borders with wooden slabs, so it's fairly easy to see where the lost chunks are at the moment.
It could be really helpful if, when claiming a new chunk, slabs spawned automatically like they do in the Wilderness world.