kiki wrote:
I had a solar system installed on my rooftop by Bilt-Well a few years
ago. They had damaged my rooftop and causing a large amount of
leaking since then. After I contacted them(numerous times), they
said they'd no longer in solar business and will not do anything to
fix the problem.

It really doesn't matter what their current business is. If it is the
same company that originally installed the system (and they provided you
with a warranty against roof leaks) then ask them in writing to honor
their warranty. If they say no, or you get no response to a certified
demand letter, then contact an attorney.