Hi @csamsi, thanks for posting.
Could you clarify what exactly you were wanting to do? If you no longer wish to keep the service, you can cancel your Website Builder plan, If you were wanting to do something else, either follow up with more details and perhaps a Community member can offer some suggestions, or call Support to review your account with you.
Canceling your plan will remove the website and permanently delete any files related to the site. If you recently purchased your plan, I do suggest that you review this with Support first to see if it's eligible for refund.
You can use the steps in this article to cancel a service: