Hi, We have a 2017 Precept 31UL and the shower head holder attached to the shower wall is getting loose. Can't find any screws or allens to tighten; I suspect they are behind the tiny pieces of white plastic that are in 2 small round holes (one on the top and one on the bottom of the holder). Is that correct and if so how do I get the pieces of plastic out (w/o breaking something), they have flat surfaces and are recessed slightly below the surface? Thank you.