Hi there, Nabilmss. It seems like your customer has an existing credit. QuickBooks Online has a feature that automatically applies any available credits to new invoices, which is likely why the system marked it as paid immediately.
To resolve this and prevent it from happening again, go to the Gear icon > Account and settings > Advanced > Automation > Edit > turn off Automatically apply credits > Save.
Once the setting is adjusted, you can reverse the payment by clearing it. Here's how:
- Go to the Customer Hub, select Customers & Leads.
- Find the specific customer and click on their invoice.
- In the panel that opens on the right, click the View payment # hyperlink.
- On the payment page, uncheck the box next to the invoice to unapply the payment.
- Hit Save and close.
Let me know in the comments below if you need additional assistance managing your invoices.