Contact Antillephone directly: You can reach out to Antillephone's customer service team to inquire about the casino in question. They should be able to confirm whether or not the casino is licensed by Antillephone.
Check other third-party websites: There are several third-party websites that list licensed online casinos, such as eCOGRA, GamCare, and the UK Gambling Commission. You can try checking these websites to see if the casino you're interested in is listed as licensed.
Look for other signs of legitimacy: Even if you can't confirm the casino's license, there are other indicators of whether or not it is a legitimate operation. Look for things like a secure connection (https), customer reviews, and information about the company's ownership and management. If you can't find any of this information, it may be best to steer clear of the casino in question.
It's always important to do your due diligence before gambling online, and verifying a casino's license is just one piece of the puzzle.
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