Kontakt 7 not working

It feels like to me Kontakt 7 is now obsolete now Kontakt 8 has arrived, and they want me to pay £89 for it to work again.

You should absolutely not interpret any of that way or buy Kontakt 8 based on that Kontakt 7 does not work for you, get the problem fixed instead.

Native Access downloader it gets to Installing but then just stays on "Installing" forever, and does not install it.

Since Native Access does not have any worth mentioning self recovery from failed downloads then that sometimes can be hard to fix other than to remove the failed download from download folder and remove Native Access' information about the download by uninstalling N.A. and then also remove anything Native Access from drive and then re-install N.A: . But it might be better for you to ask Support to help you fix the problem. Contact N.I. Native Access and Installation Support .

But at least then be sure that you are using latest version of Native Access for your OS

I also cannot contact any help from customer service as this box will not load either.

In case that you need guidance contacting support : How to contact NI Support and How to get in touch with our Customer Care

Web page functionality or lack of same could be a browser issue then also try another browser with no extensions and all cookies accepted (my suggestions for alternative browsers would be e.g. Firefox, Chrome, Vivaldi browser and Opera browser , depending on what you do not usually use)