Nixvue Vista website
I've had the same problem, and my interpretation is that the manufacturers may now be out of business. However, there also could be other reasons that their website is down.
The kind folks at the Fred Miranda Gear Talk Forum told me that the Nixvue products now have a new distributor in the U.S.:
As closely as I can tell, this is the current U.K. distributor:
Hope that assists you.