I've purchased this game but I'm not sure that I'll be able to continue playing after the free trial period since I'll probably be moving to a different city and I'll have a lot of things to do. I'm just afraid that they will automatically bill me for the next month if I don't cancel and when I click the cancel button, I get the message that I should call the customer support or something. What's going on? Is there something wrong with my account?
If you're able to play normally than there's nothing wrong with your account. The thing with the subscription is that they have to make it a bit complicated so that they are sure it's you that's canceling your subscription and not someone else. So indeed you'll have to dial that number they've told you to. Don't worry, it shouldn't cost much.