When you buy something off the EE, you're probably paying less than you'd pay a retailer... so why does everyone expect service that's superior to that which you would receive from a retailer?
At a store, selling you things is their business; it's all they do, every day. On the EE, you're dealing with people that lead regular lives, and have other #### to do besides holding your hand throughout the whole process. Is communication nice? Yes, undoubtedly, that's why I try to communicate well with my buyers and seller. But as long as you get what you paid for, and it's in the expected condition and delivered in a timely manner, I don't think any complaints really have a leg to stand on.
The EE is not a retail outlet, it's a classifieds section. Adjust your expectations accordingly, do your due diligence, and most will find they are rarely disappointed.
As an aside though, photo collectors and time-wasting, over-negotiating, question-filled buyers trying to horse trade and/or nickel and dime you to death need to stop being dicks when the item they've been asking about for days sells out from under them to some guy that just says; "Here's the cash, thanks."