The renewal of a domain is handled by One.com, who therefore charges an annual domain fee. The only exception is the .dk domain which is managed and charged by DK Hostmaster.
However, since a domain's contact information is obtainable via public so-called WHOIS databases on the Internet, it happens that certain companies attempt to wrongfully charge a domain fee.
Companies with a business model based on this unethical practice are Domain Renewal Group, Namejuice.com and Domain Registry Of America (DROA). There exists no complete list of such companies, and the same firm may operate under different names.
The company's method is mass sending of invoice-like letters and emails to domain owners while pretending to be the rightful registrar and accountable for the domain's renewal. The company does not clearly unveil its intentions, but the aim is to convince the owner to transfer the domain, giving the company control over the domain for a number of years.
When a domain owner enters into an agreement with such company, it will often turn out to be very difficult for the domain owner to change hosting provider during an expensive contractual subscription period.
If you are in doubt of how to react to invoice-like requests regarding your domain, sent from anyone else than One.com, please contact our support before paying the invoice.