All appeals must be submitted online within 28 days of the date of issue.
On or before 20 July.
I'm afraid you dropped the ball on 2 July and they won't allow an appeal now. You can always ask, of course.
It is more likely that, if you don't pay, Bay Sentry will engage debt collectors,
DCBL, followed by a Letter of Claim and a county court claim by
DCB Legal. If you engage with the process you can use PoFA non-compliance in your defence, and it's likely that DCB Legal will discontinue the case before having to pay the fee, but before they you have to pay attention to deadlines and paperwork or you'll just end up with a more expensive default judgment against you.
If you want to follow this route, you will get advice here but you need to own your side of the process.