VAT is a European-based tax, and Seller Labs is a US-based company. We do not have a VAT number, so we cannot provide a VAT Invoice.
To access your invoices, log into your Seller Labs Account. Click on your email in the top right corner of the screen, and from the dropdown click on "Account". From this page click on the "Billing" tab, and you can view each invoice under "Payment Activity". If you click "View Invoice" in the Action column, it will give you a full page version of the invoice.