Congrats good work.
Yes, but you need to have the full right to sell it (signed agreement).
First sale is the most beautiful
It is obvious that the authors are trying to be the best, but no need to take everything personally. Directly contacting the buyer is not correct. People have different views on the same thing.
Everyone has the right to rate purchased items as he wants.
Welcome on board
It still needs some improvement, but I think this site is starting to look really great!
You can place your collections also with some basic HTML code if you want!
Edit Profile: My settings > Personal Information > Profile Text
<a href="http://graphicriver.net/collections/link-to-your-collection"><img width="260" height="140" src="http://www.yourimage.png" alt="My personal collection" /></a>