It's not really the shop's fault, why should they be responsible? They bought from Siglelei as well, and ideally should deal with them directly for an exchange the same way a customer would, but apparently Siglelei only offers them one option: buy. Vape shops don't manufacture, just resell. Siglelei seems popular = $. Siglelei appears only interested in quick $ or don't speak English. Lastly, it does suck but $120 isn't that much. If you smoke a pack a day for $12, it's only 10 days smokeless.
I don't get why vapers are so cheap. Real smokers pretty much rich after switching.