My card was charged twice by Capitaldiscoveries (capitaldiscoveries.com) on the same day. I had to dispute it with my bank. Capitaldiscoveries (capitaldiscoveries.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: Helpful community forum|API access|Transparent fees|Automated trading options
Cons: Some tools only available on higher tiers