This means that if you want to use a VPN, whether free or paid, you need to confirm with the casino service first to confirm that you are using a VPN to pave the way because your IP is not limited to access the casino service you are going to.
And it would also be nice not to use a VPN at all, if we can access it without the need to use a VPN, there is no risk whatsoever and we can be much more free to access or visit the casino.
AFAIK, usage of VPN is allowed so asking the support will not give the clear answer which depends on what IP that you have used to access and its on our own that is why it's better not to use VPN at all or pay the premium and get dedicated proxy address for privacy purpose to avoid exposing your internet activity to your internet provider and nothing else.
Maybe VPN usage is fine if you are in region which is not been restricted by their management.
But if you are in those restricted list countries then better not to use it just to bypass the restriction since still you might really encounter some issues since I maybe guess that this is not allowed to do. If they are still skeptical regarding on this and to avoid getting any further confusion towards certain implementation or usage maybe they should contact the support if they have time.
But if they don't have or they are shy to ask then maybe best to avoid using this app or tool so that they can stay away on any possible issues that might trigger for using VPN.