After checking each of the 4 sellers' history, I don't think it's innocent seller being hacked:
each and every one of them went berserk just about
1 year after registering the account. They all had around 300~400 feedback. That seems to be the pattern. They became unregistered after eBay removed them for fraud. (FYI:
seller1,
seller2,
seller3)
Huh...well 2 of them are 1 year. One of them was started in September. That is...something, though. Sounds organized... :-(