I believe that you should elaborate in the following question, "When it will be appropriate to use the ban command?" as most of the reasons you stated may be resolved without ban.
It seems the scenario you've shown us shows you aggravating the rule breakers which of course may turn into a problematic situation. I feel like the solution to this could have been solved better unless they were full on trolls that knew better. You've also haven't mentioned informing an admin during this situation who could have condensed this mess.

I believe that you should elaborate in the following question, "When it will be appropriate to use the ban command?" as most of the reasons you stated may be resolved without ban. [quote]but they joined again and if i would be admin i could ban them that they cant rulebreaking anymore.[/quote] It seems the scenario you've shown us shows you aggravating the rule breakers which of course may turn into a problematic situation. I feel like the solution to this could have been solved better unless they were full on trolls that knew better. You've also haven't mentioned informing an admin during this situation who could have condensed this mess.