Do it yourself out-of-warranty battery replacement
Since Bose doesn't offer a battery replacement service, one might try doing it one's self, if you're handy with such things, or maybe a cellphone technician (since they are experienced working with tiny delicate electronics). I'm sure Bose wouldn't recommend it, but if it's out of warranty with a dead battery, your only official option is to throw away a $500 headset, so what have you got to lose? I did some poking around on the internet and could find nothing about Hearphones battery replacement, so I thought since they're the same form factor as the QC30, they likely use the same battery and I looked for that. I found no tutorials nor videos, but I did find replacement batteries!