Cellpex.com has been online since 2005. They are not the actual seller rather they are a large wholesale platform for mobile phones and accessories, which means you are not buying from them but from sellers registered on their site - so you are bound to meet a few scammers but relatively buyers have a generally positive feedback.
Should you decide to buy from any of the sellers from there, I suggest getting to know your seller, check out their feedback and always pay using safe payment methods.
Here are a couple of forum discussions about them - Link hidden: Login to view Link hidden: Login to view
Hope this helps :)