It is quite common for clients to ask about letter or emails they get, which seem to be telling them that their domain name needs to be renewed.
Almost 100% of the time these are a scam.
Since all information in the public registry is exactly that "public" anyone can find out who owns a domain. Criminals use this information to try to extract credit card details from un-suspecting domain owners.
If you get one of these, first ask yourself if it is where you originally bought the domain. If it is not, then discard it immeadiately.
Goldhosts try to protect our customers by intercepting these communications, to prevent any hassle.