Is there such a shop as "Evil Bay"?..... ebay?
Used?.....modified?..... or NEW?
The way I look at the dismantling.... if you are not returning it, I would suggest that you unsolder the LED display module and IPA clean, and scrub with a tooth brush the top side and bottom side of the whole board and the LED segment display. Just assume there is a invisible conductive liquid film stains on the board.
After that, dry it sufficiently.
Otherwise, return it under PainPal protection, I suppose...