Absolutely disgraceful. Vista has been available for testing for i don't know how long, and must have been completely ignored by the morons at Tiscali. I've had similar nonsense given to me by Orange, but their hardware does work without any problem.
My guess is that these idiots have simply been waiting to see if it works, instead of using the Vista betas to test their hardware etc., as you say.
From your quote it would appear that no-one at Tiscali was aware that Vista was to be released.
People should put off upgrading their system because their ISP is a waste of space. don't think so.
Time for users to vote with their feet I think.