Our new Milguard window won't close completely. The contractor said it's fine but it's not. It seems to be warped and is not straight. It lets air in on the bottom side. Is there anything I should do? I haven't signed off on it yet.

Do not sign off and do not pay him. Contact the manufacturer directly and tell them of your issue. Contact Milgard - Milgard Windows and Doors (http://www.milgard.com/care-and-warranty/contact-us/)