"Dear owner of the place,
I do not know if dear is the word to use but common is a weird language, so excuse me for that.
I was recently banned from the place because I insulted a moron who stopped me from helping a friend in need inside your building. Your chief of security told me that I should apologise to let me back in, I will never say I am sorry for that, the best thing I can offer is that I won't insult a person inside the place again.
I hope you find this suitable, because it is rather boring out here.
How do I end this letter? I guess a goobye with my signature should be enough.
Goodbye
*Mark's signature is something resembling a hawk*"