Just a bit of a joke really. I've sent an email to info@naviextras.com, which I found eventually as everywhere on that website they redirect to the Jaguar retailer, who don't want to know.
No actual reply so far, but I got this automated one:
Please note that you cannot create a new case via email. If you have an Alpine, Pioneer, Subaru Gen2, Xzent or Zenec device, please visit our case form by clicking the link below, then log in, share your issue and our team will get in touch. Available in English and German.
Link: https://www.naviextras.com/shop/portal/support
If you have a Becker, Becker Connect or Falk device, please visit the link below and select Customer Care at the bottom of the page to get in touch. Available in English and German.
Link: https://contentmanager.welcome.naviextras.com/
If you have any other device, please visit the link below to access our knowledge base, where you can find useful articles on troubleshooting common issues. Moreover, you can open a ticket to get help with matters related to purchases or handling of your personal data. Available in English only.
Link: https://nng.force.com/naviextrasknowledgebase/s/
Unfortunately none of those seem to fit this scenario, if you click the last link, there's no mention of Jaguar or any obvious way to 'open a case'. If you try and register an account to open said case, you get as far as choosing your device - 'Jaguar NGI' comes up - then you just get redirected to the original website! Here's open I get an actual reply. According to their policy attached to the invoice, you can claim a refund if your device is incompatible but how to claim that refund is not explained.