JWS88

I have a C205 2016 coupe, Iridium silver. Two days ago the painted plastic cover plate which slides onto the plastic fuel door flap via 4 moulded clips was knocked when refueling, three of the four clips on the inside of the cover plate sapped off and vanished in the dirt and the cover plate fell off.
I can buy a new blank cover plate from the mb dealer for $A135 plus an unknown amount to have it painted and then clipped into place. To save on cost I was wondering whether I should take it to a body repair shop or alternatively buy a Selleys epoxy putty from Bunnings and have a go myself.
My other car, a 2007 E350, never had this problem as it only has a painted metal fuel door flap!
Appreciate members advice.