Thanks for sharing your concern here in the thread. 

I know how important recording the tips you received and matching them to your invoice transactions is to make your account balance. Let me guide you to get you back in matching your transactions.

There are three options to record invoice overpayments in QuickBooks Online. It includes sending a refund, recording a credit memo, or a tip. Since your customer doesn't want to credit it to their next invoice, I recommend creating a tip account so you can record the extra money received.

First, you can create a new income account to track the tips. Refer to the steps below:

1. Go to the Gear icon, then select Chart of Accounts.
2. Click the New button, then select the Income icon.
3. In the Save account under, select Other Income.
4. In the Tax form section dropdown, select Other Miscellaneous Income.
5. Enter an Account Name, like "Tips or Tip Revenue".
6. Click Save.

Next, you need to create a tip item. Here's how:

1. Go to the Gear icon, then select Products & services.
2. Click the New button, then Non-inventory.
3. Enter the Name, like "Tips".
4. Under the Income account dropdown, select or enter the tip account you created in the first step.
5. Click Save and Close.

Then, you can now record the extra money as a tip by creating an invoice. 

1. Click on the +New button, then select Invoice.
2. Fill in the necessary details.
3. Select the tip you created for the Product/service, then enter the extra money you received in the Amount column.
4. Select Save and Close.

Lastly, you can now record the payment as received.

1. Click on the +New button, then select Received payment.
2. Select the customer and payment method used.
3. Select the invoice you created.
4. Click Save and Close.

Furthermore, you can categorize and match your transactions to make your account balance. 

Also, you can review and match your bank statements with the recorded transactions in your QuickBooks account: Reconcile an account in QuickBooks Online.

If you have other concerns besides recording tips, you can leave a comment or start a new thread in the Community space. We're always here to give you the support that you need. Have a wonderful day!