I can help you delete unbilled activity, @murtruns.
In QuickBooks Online (QBO), we can delete unbilled activity by going to the Reports menu. I'll guide you how:
1. Go to the Reports menu.
2. Under the Who owes you section, choose Unbilled charges or Unbilled time.
3. Click on the Activity Date link.
4. Hit Bill link.
5. When prompted if you want to leave without saving, click Yes.
6. On the Bill page, uncheck the Billable Column.
7. Click Save and Close.
For additional insights, you may check out this link: Manage a customer's billable expense charge.
You might want to read this article to learn how to automatically invoice your customers for unbilled time activities: Auto-invoicing for unbilled activities.
Should you need help with billable charges/expenses in QBO, please let me know by leaving a comment below. I'd be around to help. Have a good one.