Am I the first one? I hardly used the website, actually didn't do even 1 trade, but now they locked me out and say they only allow me back in (and get my money back) if I give a photo of myself and my ID.
How much money did you store on there? Was it a substantial amount?
I've used Bitmex for a while now and haven't had any issues. It is likely that they genuinely suspect something wrong with your account, otherwise they certainly wouldn't be trying to shut your account down without any trades on it.
Though realistically the only way you will get your funds back is through providing the necessary ID, you could try negotiating with their customer support which I doubt will result in much meaningful results. If it's not a substantial amount, consider just moving on and using another derivatives exchange.