Its universal truth my brother, when they need money you can deposit from anything, they care about getting funds only BUT when its time to money out, every T&C appliedThey received the funds and initially allowed th trader to begin trading.
But if there is a problem with source of funds, why not just reject the deposit from the beginning?
But even if it was a mistake, they would have refunded the credit card immediately. No reason to hold the money hostage.
Even the regulated will be fooled. I would escalate this as a formal complaint quickly.