I'm sorry you feel that way. You posted a message on your mother's profile page exactly two weeks ago. The profile manager has not made a contribution for about nine months, so she might have lost interest or had some personal problem. I don't see a G2G message from you about joining the Irish roots project.
WT has mentors whose job is to help new members with such hurdles. Someone should reach out to you if they haven't already. Whatever happens, good luck to you.
To answer your question, I think an e-mail to info@wikitree.com can close your account.