Unknown ExtremeCloud IQ (VIQ) account.

Hi team, I am trying to unbind 3 legacy Aerohive access points from an old, unknown ExtremeCloud IQ (VIQ) account. These were deployed several years ago by a former IT staff member who is no longer with our company, and we do not have the original purchase invoices or contract numbers. GTAC is unable to assist through the standard portal without an invoice, but we have physical possession of the hardware and need to get them managed on our own account.