Hm, to theoretically, you should try to do another withdrawal if you deposit a bit more and get over 100, but I can understand that it would be too risky. It's not guaranteed you get the winnings + your deposit.
I mean, it would be pretty easy to see if you really deposited 96 as they claim or 25 as you said. It should be in your account history and if it's not there, then the casino has this information for sure.
The problem is that the casino has a very bad reputation and I'm afraid it will be very difficult to get anything from them.
Automatic translation: