Not sketchy, but if it is an item with high re-sale potential, scammers gravitate to that shit.
From post 6 it would seem you initiated the charge back before contacting them.
It is likely they deserve it... but charging back without contacting the merchant first is not very polite. Most people will refund just to avoid the charge back, which not only hurts given the charge back fees that range from $15-50, but also the fact that it can hurt the merchants standings. I'm not saying chase after them, but at least give them 1 contact and 24 hours before you initiate that shit. Even if it is unlikely, there is a possibility that the issue is due to your mistake (sending cancellation email to wrong address, server issues, not noticing you signed up for more than just one recurring charge and cancelling only one and not all, etc)
And no, the scammer tag was not written by me.