Is there something with a server update or something? I had over 470 spots on my map and I logged in this morning and it has reverted back to an old save with only 266, and a bunch of stuff that was added in by another user that I had already removed. Is there a way to retrieve a previously saved copy from a certain time yesterday?
Sorry for your situation. Did you try to edit the map together with multiple users at the same time? Unfortunately it can happen, this is why collaborative editing is not supported at the moment.
The best thing is to regularly export the GeoJSONs, then you’ll never loose any change. Also, I’m working on making automatic versioning in MapHub.