They probably wouldn’t have known if you hadn’t won and subsequently tried to withdraw, if you used a different email address, it’s the sort of thing which would only come up during the due diligence on withdrawals. But then you said you were verified which makes it at least interesting that your name and date of birth wasn’t flagged at that stage. Were your address and card different too?
It’s unfortunate but entirely fair by the casino. You’re getting your deposits back, unlike the guy who posted here recently about Mr Green.
I sincerely don’t mean this unkindly but I don’t tend to have much sympathy for people when they complain about casinos in any way which amounts to “Casino won’t pay out because I [insert obvious violation of terms and conditions here]” – I know it can happen by accident and it sucks and I feel for you to that extent, but ultimately it is as much the player responsibility to check these things and know what they’re signing up for and what they have signed up for. Self exclusion and bonus restrictions are the ones people most commonly fall foul of.