I appreciate you for following the steps above and for coming back to the thread, Ak2020. Let me discuss how balance works in QuickBooks Online. Then, to ensure that you can still record the remaining balance so the customer can pay it.

When you create a sales entry or invoice and the initial payment is being recorded, QuickBooks applies the payment to the invoice line items in the order. Then, the remaining balance will show as open on the customer's details or you can also run the Customer Balance Summary report to see it. 

Additionally, the open balance will only be tagged as close once payment is complete by making another received payment or deposit.

On the other hand, you also have the option to create a journal entry in QuickBooks so you can update the balances and the record is in shipshape. Beforehand, I suggest consulting an accountant to help you further. They'll be able to provide you with suggestions on how to properly handle the transactions, especially with the category or account to use for the debit and credit.

Here's how:

1. Select + New. Then, choose Journal entry.
2. On the first line, select an account from the Account field. Depending on if you need to debit or credit the account, enter the amount in the correct column.
3. On the next line, select the other account you're moving money to or from. Depending on if you entered a debit or credit on the first line, enter the same amount in the opposite column.
4. Enter information in the memo section so you know why you made the journal entry.
5. Fill in the other necessary field.
6. Click Save and close.

Lastly, you may refer to this article to see various details on how you can enter a balance for a customer that owes you money: Manage outstanding balances for customers and vendors in QuickBooks Online.

Feel free to get back to me if you have additional questions about the customer's balance in QBO. I'm always here to help you out, Ak2020. Have a great day!