Invoice says paid without the customer actually making a payment?

Welcome and thanks for visiting the Community today, @bijayaryal. As an insight, invoices won't automatically be paid or applied for the existing credits when the Automatically apply credits feature was turned off from the Account and Settings. 

Let's ensure that this feature is off from your settings:

1. Go to the Settings (Gear icon)menu.
2. Select Accounts and Settings.
3. Click the Payments tab, then go to the Automation section. 
4. Uncheck the box for Automatically apply credits.
5. Click Save, then Done. 

In case this settings is already turned off and the invoice was marked as paid, It could be that the invoice was accidentally marked as paid. We can check your audit log to confirm. I'll show you how: 

1. Click the Gear icon, then select Audit Log. 
2. Filter the transactions from the Filter drop-down arrow, then click Apply.
3. Locate the invoice and see who received it.

Then, follow the steps to remove a payment from an invoice in QuickBooks Online (QBO):

1. Open the invoice. 
2. Click the blue link "1 payment made" just below the PAID status. 
3. Click the date of the payment.
4. Select More at the bottom and select Delete.
5. Click Yes. 

For future reference, check out this link to learn more about voiding or deleting an invoice or other transactions in QBO.

Let me know how it goes or if you need further assistance. I'm always here to help you more.

Hi there, @bijayaryal.

Hope you’re doing great. I wanted to see how everything is going about the invoice concerns that were marked as paid you had yesterday. Was it resolved?

Do you need any additional help or clarification? If you do, just let me know. I’d be happy to help you at any time.

Looking forward to your reply. Have a pleasant day ahead!