Looks like it's one big mess, since i doubt there are that many people who don't bother claim their losses. The news doesn't mention what will happen to unclaimed $2.5 billion either. Your opinion is greatly appreciated.
I don't know why those users did not verify their accounts. Probably, they don't want to hand over their documents to the authority because I believe those documents will be reviewed by the authorities. Also, there is a possibility that a large number of their users didn't know that they would have to complete the KYC. But I think they should be notified via email about the KYC verification.
Anyway, the amount is big. We don't know what they are going to do with that 2.5 billion dollars. I guess they are still in touch with the authorities.