You can contact a game creator to report an issue with in-game items or passes or have a private conservation with your friend by using the messaging feature.
Sending a Message
To send a message, go to your Friends section and click on your friend's name. This will take you to their profile. Press the Message button in the box at the top of the page that contains their username and friends and followers information.
If you are not already friends with the person that you would like to communicate with, you can still send them messages as long as you and they have allowed this in their privacy settings. To find them, type their username into the search bar at the top of the screen and choose the Search (username) in People option in the set of choices that will pop up. Click on their name in the list of search results and it will take you to their profile where you can click their Message button.
The Message Button Won't Let Me Click It
If the person that you are trying to message has a Message button that is not clickable, then their privacy settings might not be set up to allow private messages at this time. Additionally, you will need to make sure your privacy settings would allow them to message you back. For example, if you only allow your friends to message you and you are trying to message someone who isn't your friend, the message button would not be able to be clicked. For more information on privacy permissions, please click here.