Agree it's an Easter egger cockerel, but I'm thinking more like 4 months, not 7. Unless you've had the bird that entire time and are positive on age, I'd say the seller was mistaken. I'm sure the seller thought it was an Ameraucana pullet, because that's what they bought from the hatchery. Hatchery sexing is only 90-95% accurate, Oops roosters happen. If the bird was sold to you as a pullet, and you paid pullet prices, you should contact the seller and let them make it right for you. I seriously doubt there was ill will involved, so go on the assumption they'll want to fix things for you.