This problem does happen while using mobile phone, surfing in many other particular sites.
This happens simply because the screen is smaller, and it is harder to control the item while surfing in the internet since the screen is small and you might be pressing another button instead of pressing the "agree to the rules" button. Make sure that you are pressing the right button, and watch closely to where it leads you. Just be careful about what you press on.
It might be also a bug of the mobile phone site. In this case, talking to the administrator of this site is the best thing to do.