Plastic like that gets brittle and it looks like you need to replace the splitter you could buy a cheap power splitter board and cut the wire and rewire it into the ups.
What do you mean by "rewire it into the UPS"?
I assume you mean to throw the old splitter into trash can but transfer all into new power splitter board? One person suggested throwing everything in trash since contacts seem to be badly engineered.
By the way guys, when i bought UPS i asked the company for UPS power splitter which is this one. When i got it, i lifted it up and heard sounds like something is moving within which appeared to be plastic. I am surprised such company would send me this junk.