My card was charged twice by Ymcoin (ymcoin.com) on the same day. I had to dispute it with my bank. Ymcoin (ymcoin.com) then froze my account and said I had a negative balance because of the chargeback. They created the problem and then punished me for it.
Pros: Responsive team|Two-factor authentication|Segregated accounts
Cons: Research section could be deeper