any comment on this shop

[dr. d]

Mga sir ano ba yung madalas tinatamaan sa ilalim ng kotse pag sumasayad ng humps? Pano ko malalaman kung may damage?

it can be anything.
sometimes, it is not the lowest part of the undercar.
sometimes, it depends on where the tumatama is located.
oil pan (yikes!).. tambucho.. lower shock mounting.. floorpan.. bumper!
look under the car, po. if the sound is as loud as you describe, there should be marks.
have your car lifted at a gas station, to make the search easier.

pag may punit, kitang kita yan.

if metal, sometimes the part that got hit is shiney, or rusty, depending on water... pintahan nyo po, kahit red lead. para hindi kalawangin.
sometimes, the paint wasn't abraded off, but there is a noticeable shiney depression...