generallyv vinyl siding should be hung loosely, i.e. the nails should not be hammered down all the way and the siding should be allowed to move to accomodate for expansion and shrinkage of the siding due to temperature variation effects. get a second and third opinion on the cause and correction . Those should be free opinions and repair estimates and then use those to demand the installer to fix at no charge. By the way why did the original installer believe it was bucklying? good luck LJ