I agree that's a cockerel (young rooster). If you just purchased the bird, and paid for a pullet, the seller needs to make it right with you.
I agree with the above, pullets (young females) are plainer colored. The bright, flashy colors are male.
If you're unsure about gender, feel free to get pics before you purchase and post them here. There's usually someone around who can ID the gender for you and save you some headache.