A few businesses I work for have gotten notices looking similar to the following:
Often the accounts department will simply pay these, not realising what they exactly are. In my experience, they are usually registrations of domain names that are close but not exact to your own domain name.
As a result, the company sending the bill make $250 odd dollars, and you are none the wiser, not realising that the the domain you just paid for actually has no use and goes nowhere.
If in doubt, speak to your web / email provider.