They're asking you to LIST your other accounts in their casino because if you have two or more accounts, then you have broken their rules which you have signed not to break during registration. They are also sort of sure that you have more than one account, which from the chat, you never addressed. You merely posted your other complaints in CasinoGuru.
I saw some user who was asked the same questions, and they kept insisting. It seemed they we so sure about it only to unlock his account after some days.
Who is this user and what actually happened? I believe we should hear his/her side of the issue. That situation might be something to learn from if our accounts, despite being innocent, might have the same issue. Can you post the links of his posts?
So where is exactly the line between someone who is guilty of having multiple accounts and someone who's innocent.
Do you believe that they are merely guessing?
If you don't have more than one account, then tell them, AND ask them HOW they concluded that you have more than one account, or WHY are they accusing you.
I think he has already told them so, but they keep insisting.
He/she should also ask them HOW they made the absolute conclusion that he/she has more than one account.