Since you're aware of the situation, I am unable to help you. This was not a smart decision on your end, and you should have known that it was severely against the rules to Mass freehit leading to Mass freekill (because you're pyro and do tick damage). It was even worse for you to leave after which extended your punishment. You have around 9 hours and 15 minutes left in your guardban and I think that you should serve out the rest of your guardban to to brush up on rules and overall knowledge of the server so that this instance doesn't happen again. Feel free to message me if you have questions.
Appeal Denied.