When an account is banned, do the funds disappear, and what happens to them? Does the administrator have access and can just withdraw and transfer everything? Or maybe that’s not possible and everything stays in the wallet?
You won't get anything if they banned your account. The funds will be confiscated. How can you mess up like that by keeping big amounts on your account? Does the account of your sister belong to your referral list (or vice-versa)? Also check your mailbox whether you have received an automatic password reset email from them since this problem started to happen. They won't ban the accounts just like that unless you and your sister has made any abuse.