You can block people so they can't contact you.
In a room:
- Swipe from the extreme right side of the screen to the left
- The list of people in the room will appear
- Tap on any name then select 'block user'
If you are in a private message:
- Tap on their profile picture
- Select 'block user'
Block anyone that you have already added to your Pal List
- Tap on their name
- Selecting 'block user'
As you can see, you have the option to block any user at any time in any window that they may be disturbing you in.
Once you block a user they can never contact you on that name again.