I recently had my A/C unit replaced in the attic. The unit was about 20
years old and the pan was in bad shape. When the repair company
initially replaced it they didn't replace the pan for some reason.
Later they came back to replace the pan but apparently put in one that
was too small, which caused water to leak out. There are visible water
marks on the ceiling in one room.

They have admitted that it was their mistake and have offered to fix it
for free. Obviously, I no longer trust these guys so I tried to get my
home warranty company to send out another company to assess and fix the
damage but they don't cover secondary damages due to attempted repairs
to the initial problem. Should I bother having another company come out
and assess/fix the damage at my own expense? Is this an expensive
problem to fix? Is this a difficult thing to fix (i.e. is it in their
obviously limited scope of abilities)?

Any advice general or specific is welcome.

Thanks,
Dave