Cut this buyer loose and get a new one, if the buyer is pushing the roof when there is nothing wrong, you may be wasting valuable time, NOT being on the market, which will cause you to lose the REAL buyer that is out there looking for your home.
If there is nothing wrong with your roof a buyer cannot ask for a new one and this buyer is wasting everyone's time by being unreasonable.
Best of Luck,
Josh Barnett, Realtor
Metro First Realty