You can't change feedback. You can mutually withdraw it, but you can't change it from negative to positive. I don't see why anyone thinks eBay should shut them down. Obviously if you are a good buyer you can look through their feedback and decide whether or not you will do business. If things are really as horrible as everyone says, they'll be shut down by their own means. Even if 50 people had reported negative feedback over the past month, that still leave ~97% of the customers either neutral (mostly due to slow shipping) or perfectly happy.
why dont you read the link before you ask questoins that have been addressed in it?
and if you can't understand why this place needs shut down, then you've obviously never been scammed.
