Without fail, every time I apply to register a trademark, either I or my client will receive in the mail an "invoice" from some company I've never heard of. It will be styled in neutral, official-sounding language such as "filing fee" or "application fee," and on first glance there will be no indication that I have any choice in whether or not to pay. Tellingly, the address for remitting payment is almost always somewhere in Eastern Europe. I was reminded of this just a few days ago, when I received an invoice for $1,560 from "TPP - Trademark and Patent Publications" related to a US trademark application my client had recently filed.
If you receive a similar invoice, do not pay it. IT IS A SCAM. Simply typing the names of these companies into Google will reveal the same thing; no less than the World Intellectual Property Organization (WIPO--which is a real entity) lists TPP and dozens of other similar "companies" on its list of known scammers. The amounts being charged (including in this case) are exorbitant--in this latest instance, more than the actual filing fee and related attorneys' fees combined--and give no explanation of the "services" being charged for (because there aren't any).
These invoices are also great reasons for businesses to educate their staff on vetting all requests for payment. Evidently, some enterprising individuals in Eastern Europe clued into the fact that, when corporate functionaries receive a bill in the mail, they will pay it with few questions asked--especially when it appears to relate to something they know exists, like a recent trademark application. It must work often enough to make it worthwhile for these "companies" to keep trying, although the frequent name changes of the payees may also suggest that people often catch onto them as well.
The fact that these scammers use targeted, company-specific information in order to extract a response makes this a form of "spearfishing" attack. These are often used to extract not only payment, but also identification data that can be further exploited. The fact that they often appear legitimate on first glance is what makes spearfishing the most successful method for hacking corporate networks.
Be vigilant, especially because these trademark-related scams have become so incredibly common. Know what and whom you've agreed to pay in connection with your trademark applications, and question any invoice from TPP or similar entities.