Based of my perspective and seeing these. I believe, these regarding the document you are submitted for the "KYC" is not because your country or resident is have restricted law regarding gambling.
1. Cause the lock is happening after you submit the "KYC", meaning there has somethings wrong with your document is being submitted
2. Vietname is not on the list restricted country based term & condition BK8.
Now, I will waiting BK8 response side. But, I'm sure these regarding the document not because your law country regarding gambling.
They are scam site. If i loss. Nothing happen. That is all.