Before a Ranked Battle, you need to complete Designated Matches (shorter battles) in order to get access to the next Boss. If you don't want to complete all of the Designated Matches, join only the ones that match the gem/coin: Large Gem/Coin - Red Waypoint Small Gem/Coin - Blue Waypoint Once all your grey gems are filled, you'll be able to use the ATM to pay fees for the Boss battle.