Well, giving them the benefit of doubt, I would say that they might not actually be trolling, in fact, they may not even be sending that mail now, its highly possible that the mail you got, or we got (since I also get such emails occasionally too) may be automated in their system.
This is to say that the management of the casino have progammed their system to send out such emails to users at a given time period, so consider this first before concluding on them trolling.

Maybe you should check your login details carefully, I just logged into my freebitco account successfully without any single issue or delay..
And yes, I have funds in the account as well, but maybe not as much as you have, but then, this is just to tell you that there is nothing wrong with the login system of the site, you might have made some or a mistake while typing your login details.