I'm guessing you are a new FIT rate.
Tariffs changed July 1st for probably all states / regions, but that is a different thing to your FIT, and doesn't affect what you get in return for your excess production.
You were on 15c FIT and it's now 8.5c ?
8.5c is an unusual amount though, usually FITs are even cents with no part cent.
That's what it looks like anyway, a big drop.
You should have received a notification by email or letter about that, and new tariff rates.
Here is SA the standard 4c FIT for 2024/2025 dropped 50% to 2c, so wish we could still get even 8c here.