Document all dates, and take pics of each window frame. Then call another contractor and get an estimate on the repair. Send them a copy of the estimate, and ask them how they wish to proceed. Tell them they have 14 days(or whatever you feel is a reasonable time frame) to respond. I would send a certified letter, if they ignore you, have the other guys fix it and withhold payment. Good Luck-sometimes you have to play hardball, to get what is fair and right!poof