This is really the problem if they commit mistake by sending funds on wrong network since they provably get an issue for recovering it.
For users like this, the flow of non-sense argument is like.
You can make your mistake, but you can not say any platform as scam if they don't support you to claim your mistakenly sent fund back. If you do it, you were wrong with your deposit and you are now wrong with your unreasonable complain.
I guess what need to do is to send again some message and ask for possible solution and he should state that his willing to pay recovery fees which is common on exchange as I remember and maybe this is applicable on casinos to.
It's platform-by-platform basis, and you can not say that if exchange A supports it, other exchanges must do it, and the same wrong thinking with casinos. They can support you or not but if they say No support in ToS, your chance is very small.
Yeah, maybe the chances are really small. But still, this user should try to communicate with them, because, as this user of our forum writes, a rather large sum is frozen. And of course, losing such money is very unpleasant for any player and sometimes even almost catastrophic. In any case, you need to continue communicating with the support, maybe it will help. Well, and if it does not help, then at least identify the problem that this casino should still resolve with respect for its customers.