Well since they are not really playing "nice" why not just buy the new battery, claim it's not charging, have them send you a warranty replacement and you now have three perfectly working batteries for $592.00?
I'll even take the one you have now for $250.00, once you have working ones, if you put it in the replacement box and ship it to me as I'm convinced it's just the fuse (my email is on my profile).
I've asked them to send me RMA or whatever for parts I've had to warranty and I've never gotten one they just say keep the parts (ended up with a spare controller for wife's City 5+ HS plus a throttle and wire harness) but they may be more strict with battery.
They are not being intellectually honest with you so first I would probably ask to speak to a supervisor (and then immediately ask for their supervisor - trust me I've worked in major company call centers) and ask them to explain how, as a company with advertising based around being environmentally friendly, you paying $592.00 plus the environmental costs of shipping and then throwing away what you know is a perfectly good battery because they refuse to warranty replace it (due to the fact they have a poor design, that is not easily serviceable in the field) is going to help anyone? And, oh, by they way, I've already expressed my frustration on the forum and to anyone else who will listen. then ask "are you sure this is how you want to handle it"?
They might come up or find they have a different idea after that.
It's worth a shot, I mean obviously my first suggestion has questionable ethics. Actually you could just tell them what you intend to do if they don't find a better solution.