there are a few Highlighted Marks in the store when u are trying to upload the items.. they(the marks) are asking you ... do you own the copyright of the images...assets etc? meaning if one of ur stuff included there is not your's scirra can reject your zip file. you are asked like 3 times before you press the upload button not sure how you didn't seen it !
and as kyatric said... you should read the seller agreement.... i mean its a business.... you should read the papers...
(ps. is that the avatar that has a overlaid banned user text? or ur account got banned? im confused...)