Any one who are in forms can please answer this question

I am selling a theme to a script which cost 23. It took around a month to build the theme. Codecanyon is taking 55% from every sale. And i got one sale i receive 12.50. Now the theme is out in nulled websites. Just let me know why codecanyon taking 55% from each sale? What its helping?? Does it protecting our codes ofcourse no. Does it market our product no. Just to upload a script in their website they are charging 55%. You might ask a question then why did you upload in codecanyon i thought it was best i never tried before. The greatest thing is one of the guy who downloaded from nulled websites asking me to fix the bugs in the script for free. What to do??