Take a Look at The Customer Support
Reputable online casinos will have easy and convenient ways for players to contact them. The customer support might be 24/7, which you will find with a lot of online casinos or will have dedicated times.
Have a look at how you are able to contact the casino. Do they offer a toll-free number? Can you send them an email? Do they have live chat?
You can also test the customer service by calling them or sending them a message and see how long it takes for them to reply and if they were actually helpful. The customer support should be efficient and fast. You should time how long it takes for the support to get back to you as this what you can expect if you have a real problem. If you wait a very long time, then the customer support isn’t very accessible.
An online casino should offer different ways for players to contact them.