#1 As I mentioned, it was available at many registrars when I tried to register. It isn't an enom problem, for sure.
#2 z.cn, x.cn are developed websites..why can't y.cn be available as well? It says "no match" in whois rather than "reserved" like rest of the one letter domains.
#3 I've already sold it for $,$$$ so it doesn't matter anyway.
#4 If it indeed turns out to be a problem, I'll gladly issue a refund to the buyer. He'll have to allow me some time to gather funds though if I don't have enough funds at that point of time.