Unfortunately there are businesses who take advantage of people regarding domain names. Have you ever received a document like this one? These are solicitations to either transfer your domain or to purchase a domain you do not need or want. Some people would refer to this tactic as a ‘scam’.
Always keep your domain name contact information up to date. Be sure you always keep your log in and password in a secure location. If you are not sure what to do or how to manage your domain name you can use a trusted vendor to maintain it for you.