After defeating another Ace Trainer inside the Snowbelle Gym, I walked onto the green platform towards the yellow platform next and battled the last Ace Trainer there. My Delphox defeated his Beartic and Vanilluxe, then I pushed the yellow button and the green one too and I finally arrived at Gym Leader Wulfric's spot. He sent out his Abomasnow first and I used Delphox's Flamethrower to defeat it and then he sent out of his Cryogonal and my Delphox defeated it with Flamethrower as well. Wulfric used his Avalugg last and it gave me some trouble, so I switched to Pangoro and I eventually defeated it with Hammer Arm. I received the Iceberg Badge and Ice Beam TM from Gym Leader Wulfric after that hard battle.