Hi sedatdrkn
You should really have this discussion with your partner or account team, but here's my understanding.
Currently, the licensing strings have not changed, so although by the terms of the subscription license you are no longer entitled to use the software, there is nothing preventing this. Veritas has traditionally used an honour system with our customers around licensing.
There has been talk about moving NetBackup to a different licencing method which could prevent use of the software once the license period ends (what this means in the ability to backup or restore once a license expires, I don't know).
Hope this helps.