Flap on optical port door broke off -- how can I replace?

The little grey flap somehow broke off on the optical port and now an optical audio cable won’t stay in. I guess i’ll have to replace it. Do you guys happen to know how I can do that? Should I try WD support?

Yeah, I’d get onto WD support about that.  It shouldn’t break with regular use, so it might (should?) be covered by the warranty.