I don't understand why they kept reversing your withdrawal other than they wanted you to play it away. I had a casino do that to me one time so I feel your frustration.
I don't understand why you was depositing when you had funds in your account.
Support at Casino's can be very rude and yes even the casino management as well.
I think they probably did you a favor by locking your account as it seems by supports chat and the casino email was very unprofessional.
At least you was able to withdrawal $6500 and as far as disputing with your credit card regarding the transactions I would be careful, especially if you live in the USA.
I am very sorry that you went through these problems.