You should move this topic on gambling discussion board because this topic is related to casino with Bitcoin involve. Move it on this board https://bitcointalk.org/index.php?board=228.0.

The casino will just use it against you in case you KYC using other person identity because they will detect the change of IP once your friend login your account to do it. Can you exposed the name of the casino so that we can help you to raise concern to them if ever they have an official account here. Overall your case is very crucial because you didn't read there ToS before you play. This is the common way of Casino to get free money from there user that playing on restricted country and using VPN to dodge it.

Does your 1500$ worth of Bitcoin is came from winnings? Because Casino always use this reason incase players won.