Avoid their first tier support. Call 855.260.5969 and get directly to second tier support.
Mine was activated yesterday - finally! The very helpful technician who helped me said the issue lies with VW not issuing a new Sirius ID for the radios after the software upgrade. Sirius does not see the RNS-510 with SW2625 as Travel Link capable. Because we don't get new IDs, their system does not allow them to offer us Travel Link without massive internal escalation.
Be persistent and polite and they'll help you out.