I have been banned in chat, but honestly I do not know what for

99% of the time a ban is something very well called for. Moderators usually make special warnings before issuing a ban, so pay attention to those. However, you can still ask the MinerGate support team to get you unbanned. The chat rules listed should be of great help to get yourself safe from such situations in future. Remember that the Support team unban is always a ‘one-time offer’.