Tim Mathews (d/b/a TopSeo.net) offered a list of 6 billion E-mail addresses for $850. I do research on Internet domains, and fell for his offer.
He sent a package with lots of files, but only 200 million E-mail addresses. He admitted it was not what I ordered. Yet he did not refund my money (as required by law, as he was unable to deliver the product I ordered within 30 days).
He kept making claims that he was going to send out new data, but he clearly doesn’t have it, and did not send it (he said several times that he had sent a new package, but I never got it, and he could not provide a tracking number).
The most important red flags before I ordered:
 When I ordered, I tried paying via credit card (as it is the only method that gives you some protection), but his site claimed that the card was declined. I now believe his site automatically states that cards are declined, as he has no merchant account.
 He requested that I pay via PayPal. That sounds OK, but he had me send it to a “Robert Smith” using a generic gmail account, not to an @topseo.net E-mail address. Some people use multiple PayPal accounts if PayPal suspends one.
If doing business with them, you should NEVER send payment except via credit card, and be sure to count what you get.