So, you didn't add anything?
The potassium sorbate is just a preservative that hinders yeast activity, so nevermind that seeing you HAVE activity.
Wild yeast isn't necessarily a BAD thing...let it go. As long as you don't identify it as an infection it should turn out interesting, to say the least.
Primary: Hard Cider, Spiced Cider, Vanilla Cider, Cinnamon Cider, Orange American Wheat
Bottled: European Pilsner, Liberty Cream Ale, Orange American Wheat
On deck: Bee Cave Brewery Kolsch, Cottage House Saison