So you aren't even aware that this is against their terms and conditions? This isn't the online casino's fault, and hopefully you should accept this as your own mistake, where you are now you only need to comply with everything they ask you to do, don't forget that this is your own fault, you have no choice.

Provide Every details and documents they ask from you, prove to them that your husband is involved, I think he should do the same too and the problem should be solved.

Next time be more careful about what you do on any online casino, and I will advice you to always find time to go through terms and conditions of any online casinos, this will save you from any possible threat or your actions.