United States Domain Authority located at usdomainauthority.com is attempting to collect a fake domain renewal via a deceptive scheme. This deceptive scheme has been around for ages and even after repeated reports against websites like United States Domain Authority that have deceived people with the BBB, the Attorney General's office, the FCC, etc, somehow they are still in operation. All the website operators do is change their names.
The United States Domain Authority Letter

United States Domain Authority
PO Box 2363
Hendersonville, NC 28793
(360) 842-0196
info@usdomainauthority.com
How United States Domain Authority Operates
This United States Domain Authority sends "renewal" notices (via U.S. mail) to people who are not their customers. They get the expiration dates correct (which can be found with a simple search) so it looks legitimate. They also use important-looking stationary with American flags and official but vague language implying that you are already a customer. Even the company's name implies that they are somehow the official gatekeeper of domain names in the U.S.
Some inexperienced website owners sometimes end up filling out the paperwork, sending in their credit card numbers, and inadvertently transferring their domain name to United States Domain Authority. This usually means they end up paying a higher fee for the domain name.
Is what they are doing illegal? I don't think so, although numerous lawsuits have surfaced over this tactic. However, it is obviously unethical and deceptive. So if you receive a "renewal" notice from United States Domain Authority, do not send it in.
A website called Domain Registry of America a few years ago ran a similar deceptive scheme.