Appeals process is explained here- [PLEASE READ] Official servers - Terms of conduct, guidelines and procedures
The specific section about appeals is below-
If you want to appeal a ban , you will first have to have read these rules and make yourself aware of them. Once you have done that, get in touch with us in the way described above and provide the following details:
Platform
Name of the Server
If on PC, a link to your Steam profile.
Clan or clan names you used to play in.
Once provided those details please wait until we get back to you. When appealing a ban, you might be required to provide any explanations or information we might deem necessary in order to consider the appeal of the ban.