For your account to be closed you will first need to be removed or made inactive against all the Supplier Lists you are registered on. You can find information on understanding your Supplier List registrations here: An Overview of Your List Registrations.
For lists that they are registered on as a Colleague, you will need to ask your Vendor Admin to remove you as a Colleague. There is information here on how Vendor Admins can manage Colleagues: Suppliers Adding and Removing Colleagues.
For lists where you are a Vendor Admin, you will either need to transfer these lists to someone else or be removed/made inactive on the list. As Supplier Lists act as a contract between Suppliers and the list-owning organisation, you will need to contact the List Owner and request the list be transferred to another user or your profile be removed from the list.
You can find instructions on how you can request the List Owner to transfer a list to someone else here: Transferring a Supplier List to Someone Else.
You can find the List Owner’s contact details by selecting Supplier lists you manage under the Admin Tools menu (either in the top menu-bar or on the homepage on the left-side menu).
This page includes the details of the lists that you are registered as the Vendor Admin. You can click on the list name (in blue) to view the list’s details and relevant contact information.
Once you are no longer registered on any active lists you can contact VendorPanel Support and ask to have your account removed.