That's excessive.
Look up the price of a handyman in the Atlanta area.
$50-$80 an hour seems typical and fair.
Assume $80, and that it takes an hour to cut and patch the drywall, another hour to paint it, and then another hour to attach the holder.
That would be $240 to fix the wall, make it look nice and reattach the holder.
Add a $100 "ugh, why are you making me call a builder" surcharge and you're still a ways away from their quote, and that's with a high rate and pretty ridiculous estimates on how long it'll actually take.