Where did you buy this bike? Was it brand new from an authorized dealer? I didn't see mention of that in the OP. If the bike was sold new from a shop that is an authorized dealer for Kuota, I'd say you have a legitimate gripe and shouldn't put up with lousy service like that.

If on the other hand, the bike came for some non-authorized online seller, or was purchased used, then there is no warranty coverage of any kind, and that might be what you are running into....