As a user, when you want to delete your account, you can go to your account’s preferences (https://idp.jnctn.nz/Identity/Account/Manage/PersonalData), under the “Personal Data” and download or delete your data from here.
This will remove your account and the data associated with it, such as your email.
Please note that this will not delete the data that you have shared with your organisation or others. You need to contact the organisation for this.