Short answers for the last days of a billing period. The full rules are in How ticket usage is billed.

Why are late-period tickets missing from this invoice?

Tickets created in the 5 days before renewal (from the cutoff moment through renewal) wait for the next invoice. That delay is on purpose: your team can still mark spam or invalid. Those tickets are not dropped.

When is this invoice frozen?

1 day before your renewal date. After that freeze, the count for this invoice does not change.

Tickets already in this invoice’s window can still be marked spam or invalid until that freeze. Tickets from the last 5 days can be marked until the next freeze.

I canceled. Do the last 5 days disappear?

No. Remaining valid tickets, including those last 5 days, are billed on the last invoice.

I marked a ticket spam after I was charged

A closed invoice does not change. If the ticket is still waiting for a later invoice, it drops off that one.

Where is my renewal date?

Settings → Subscription.