Iris, to buy Premium with ebs, find someone who is willing to purchase Premium for you with their own real world money, and then pay them back in ebs. You will need a lot of ebs!
Mango the transaction won't go through and the horse will remain in the auctioner's stable. A lot of times if you free up space later they'll be willing to sell the horse for what you bid.
Lunar Tale is observing Solar Eclipse head on by riding it! She took her moon colored foal and is running across the moon right in between the earth and the sun!