UPDATE: apologies for the late reply, we are human as well, and enjoyed the Easter break.
OP poster has been notified of repeated serious ID verification failure and following double spending fraudulent behavior, we have decided to close his account and offered to return his deposit of 15 BTC.
Sportsbet.io indeed allows instant betting at 0 confirmation deposits on blockchain for player experience (except for known double spending patterns) and instant withdrawals after 3 confirmations of initial deposit. As any other BTC gambling operator offering the same, can attest to, there is a significant amount of abuse attempts around and we are simply preventing fraud here.
In a perfect world, we don't like having to KYC our players, except when absolutely necessary, and especially when certain players groups make multiple accounts and attempt to fraud us, through double spending.
We believe the experience for the player is best when they can play instantly with 0 confirmations, however, we then need to mitigate fraud, which includes knowing our customer and ensuring there are no multi accounters.
Regarding regulatory sportsbet.io is regulated by Curaçao license as stated in
https://sportsbet.io/about/gaming-licence, and we do have regulatory requirements to follow, which we continue to do so.
Best regards,
sportsbet.io
You keep claiming a double spent transaction without showing any proof. It isn't true simply because you say so, back it up.
At least the Op gets their deposit back if your offer is genuine. Other bettors beware though, this can happen to you to whenever they feel like it.