I would ask them to point out the specific part of their agreement that they are trying to enforce. If it is this section, ask them to define "minimum percentage" and consider trying to meet that obligation.
OP already lost the $500 he deposited, so he can't fulfill the wagering requirements anymore. I agree that Duelbits needs to be transparent regarding the percentage of a deposit that needs to be wagered. Saying only that "
there is a minimum percentage that needs to be wagered" is not enough. What is the minimum? 10%, 20%, 50%...? And also, is the percentage the same if you deposit $100 as it would be if you deposited $10.000 in crypto?
The other thing I would like to know is why was the player's account limited? if what he is saying is true.
Based on the chat logs, everything seems ok. You deposited some money and tried to withdraw it immediately. The casino refused to do that and claimed your coins. After you talked with the support, your money was returned to you. You gambled and lost. No scam there whatsoever. The only unclear situation to me is the betting limit that was placed on your account and why they did that.