I wouldn't play with VPN since it's breaking their rules, I'm really looking to solve this. It's really sad when you want to play on specific casino but there's a barrier obstructing your desire. I know there's an alternative casinos, but I have some personal reason to play in specific casino...
Even if it's tempting don't, you'll face issues sooner or later, the easiest way to solve this issue is to ask their support, on their channel, on their social media account, or if they have an announcement here post on their announcement, do not assume ask them directly to get the right answer if they tell your country is not ban then it's your side that has an issue like your ISP, you can then change your ISP if you really like to play on that casino.