Gamdom is indeed no control with ut because the slot provider is the one who set's it. You should redirect your concern on slot provider support instead to gamdom since you have problem with there software limit.
Since the deposit was made to the casino and not to the slot provider then the responsible should be the casino. And if there is a problem with the slot provider then the casino should deal with him and not the user.
The slot provider offers a service to the casino, and if something fails isn't the customer's fault and he doesn't need to pay for the provider's mistake.