You are not muted on our network. If no one can see your messages / you can’t see anyone’s messages, then you might be muted by Microsoft, not us.
We are not able to help you with this form of punishment, as they are done automatically by Microsoft systems. The only way you can lift this type of punishment is by saying nicer things in chat - this will improve your reputation, and can result in the mute being lifted after a while.
It’s also possible that your Microsoft privacy settings (which can also prevent you from seeing chat or sending messages) are messed up.