I think the main problem is that you are recommending retailers. We are looking for wholesalers. I checked all of the sites you listed and most of the products (can't say all since I did not check them all) sell for the retail price or ABOVE the retail price. How does that help?
This is my main complaint with Salehoo. I am looking for consumer electronics. I did a search for a number of items and Radio Shack came up. I assumed this would be some type of liquidation page for Radio Shack, but no, it was just the main Radio Shack Web site.
You need remove all non-wholesalers from the database. That is any company that does not require customers to show a valid resale certificate. I know that this will leave your database with very few entries, but at least they will all be quality entries.