WHOIS (pronounced as the phrase who is) is a query and response protocol that is widely used for querying databases that store the registered users or assignees of an Internet resource, such as a domain name, an IP address block, or an autonomous system, but is also used for a wider range of other information.

How to remove Who.is account

No removal option to be found here.
Ask them to delete your account manually. Use the form found here: https://who.is/who.is/help