They do not freeze the account, they have the account holder sign that the 800k will be frozen in the account post-issuance of the Immigration documents
Were you on the initial 90 day visa or an Extension of Stay because, if the latter and you didn't cancel it, you are racking up 500B/day overstay fines up to a maximum of 20k?
a Non-O retirement visa is a 90 day stamp, a 12 month stamp that follows is an Extension of Stay but you can't get that without a bank account unless your Embassy still does the income affidavit