Well I would say I have not heard such from online crypto casino. Most of this type of message is liable to be scam and I would say you should just ignore it. If it where to be a real kind of stuff, they will have notify you in the online casino app, then from hence you can continue with the process or you may even chat them live or you can call the  customer support centre. But in this case all I can say is for you to ignore it.