As others have suggested, ask Amazon for a replacement and you'll get it.
Same thing happened to my DX and it will eventually break apart altogether. The stick that is, not the DX
Having already gotten a replacement DX (carefully timed for a U.S. visit) on account of a s/w error, attempting a second replacement was too cumbersome. Given I live in Malaysia I would have had to ship the replacement unit somewhere else as Amazon will not deliver a replacement set to a non-supported country. Ultimately I just removed the cracked plastic and now operate the underlying stick directly. It ain't great but it works.