I think you're question may have given me a small aneurysm and possibly summoned an evil spirit, but i'll see if i can help out.
Can you elaborate on what you mean by '
DisplayName Services Google Play Games'?
Are you just looking to fetch your games Display Name? or are you working with the GP-Games Services API?
A little more info would work wonders
example: fetch display name
Code:
var name = game_display_name;
(Returns the game name string as defined in the Global Game Settings.)