Here you can find more information on the scam alert from the US Government departments.

Diversity Visa Lottery: Read the Rules, Avoid the Rip-Offs.

Diversity Visa Scams
According to the Federal Trade Commission, the nation's consumer protection agency, some businesses and attorneys misrepresent their services when it comes to offering to help people trying to enter the Diversity Visa program. They may claim to have:
an affiliation with the U.S. government
special expertise or a special entry form that is required for the DV program
a high success rate for DV entries
an ability to increase an entrant's chances of being selected, and that
people from ineligible countries still are "qualified" to enter.

What's more, some businesses and attorneys jeopardize an applicant's opportunity to participate in the lottery by filing several entries. They also may charge substantial fees to complete the application process.
More here.

Fraud Warning: Scam Alert
Diversity Visa Program Scammers Sending Fraudulent Emails and Letters
The Department of State, Office of Visa Services, advises the public of a notable increase in fraudulent emails and letters sent to Diversity Visa (DV) program (Visa Lottery) applicants.
More here

Fraud Warning
Fraudulent websites are posing as official U.S. government sites. Some companies posing as the U.S. government have sought money in order to "complete" DV entry forms.
More here.