I can help you reactivate a customer in QBO, @komatthew.
To reactivate a deleted customer, you can follow these steps:
- Sign in to your QBO account.
- Go to the Sales tab and select Customers.
- Click on the small Settings icon.
- Scroll down and locate the Other section, then tick Include Inactive.
- Search and select the deleted customer.
- In the customer profile, click Make Active.
On the other hand, please note that a Credit Memo will created to adjust the customer's balance when you delete an invoice with an associated payment. The program has an automatic feature that ensures the accuracy of your customer's balance.
For future reference, you can check out this article to save customization on your desired report and use it for future needs: Memorize a report in QBO.
I'm always around if you need additional help with reactivating deleted customers. Take care.