If it's only causing problems with you accessing a site where you are breaching that sites terms and conditions, (I.e. Netflix) then I doubt they will have too much sympathy.
Well that remains a moot point
There are Netflix subscribers in NZ who are NOT breaking the Netflix T&C.
I have friends from the US who are living in NZ. They have had a Netflix account for years and used the same account in the US. Just because they now in NZ it does not mean they are breaking the Netflix T&C.
I dont think your ISP has the right to question you about your access to an overseas site and then make their decision based on their own conclusion that you are breaking the Netflix T&C.
If there are some genuine people here in NZ that are entitled to use the service then the ISP has no right to deny access to that service.