Store values to firebase

In the app we discussed here Retrieve all data from firebase
there is a lederscore . If someone makes highscore thε score with his name store in firebase.
The problem is ,if someone for example is the Νο1 with name Player and score 200 , then if someone else play and make highscore 80 and place the name Player deletes the Player name with 200 points . Any idea how to prevent that

See this sample for one approach to minimize the simultaneous update problem ...

One of the other online tag/value components (CloudDB?) has a block to insert an item to the list kept online under a tag, to totally avoid this problem, but you would have to sort the score list each time you refresh it for display. (That's an easy thing in the Lists FAQ)