Private organizations not affiliated with the United States Patent and Trademark Office (USPTO) often use the USPTO's publicly available trademark database to obtain applicant information, and then disseminate deceptive, official-looking invoices for fees due in connection with US trademark applications and registrations. These organizations use official-sounding names such as the "United States Trademark Registration Office" and the "Worldwide Database of Trademarks and Patents." The invoices often mimic official government correspondence, refer to other governmental organizations, and emphasize official information such as registration numbers, application numbers, and filing dates.
These "invoices" are merely solicitations for unnecessary services, such as registration of trademarks in a private registry, or services that may already be performed by reputable vendors, such as trademark monitoring services. Close examination of the solicitations typically reveal that there is no obligation to pay.
When a trademark applicant is represented by an attorney, the USPTO will correspond directly with the attorney of record and will not send correspondence directly to the applicant. All USPTO correspondence comes from either a proper "uspto.gov" email address or a mailing address in Alexandria, VA.
The USPTO is aware that scam organizations sometimes use the information from its public database for improper purposes, and has issued its own warning (http://www.uspto.gov/trademarks/solicitation_warnings.jsp) along with sample solicitations. Similar warnings have been issued by the World Intellectual Property Organization (http://www.wipo.int/pct/en/warning/pct_warning.html) and the Office for Harmonization in the Internal Market, which handles trademark registrations in Europe (http://oami.europa.eu/ows/rw/pages/CTM/feesPayment/warning.en.do).
You can safely ignore trademark solicitations from organizations not affiliated with the United States Patent and Trademark Office. Consult your trademark attorney if you are unsure about a specific solicitation.