If you own a domain and your name/address are shown on your WHOIS (the public information available for the owner of a domain) — chances are you’ve received an email from Domain Registry of America (DROA).
DO NOT PAY THEM.
While they say in their letter (if you read it) that their letter is ‘not’ a bill, it looks a lot like a bill, and they have tricked many people.
You do not need to pay them to renew your domain — pay whoever it is registered with (Godaddy, Register.com, etc).
An example letter: