We have a customer that has a credit balance on his account. I have been unsuccessful in getting the credit balance to zero. I've tried using a credit memo, no luck

Hello,

If you already have a credit sitting in the customer account, you either can apply that credit to another invoice or you can issue a refund to the customer.

https://quickbooks.intuit.com/learn-support/en-us/customer-refunds-and-credits/handle-a-customer-credit-or-overpayment/00/185759

Creating a credit memo would add available credits to the customer's profile, CXL.

I can show you the proper steps to zero out this balance. Before doing so, let's start the process by deleting the credit memo. Here's how:

1. Open the customer profile. 
2. From the transaction list, open the credit memo you've created by double-clicking it. 
3. Click the Delete icon at the top. 

Once done, let's proceed to creating a refund check. this transaction will help offset the available credit. Below are the steps to do this:

1. Go to Banking at the top. 
2. Select Write Checks. 
3. Enter the bank account and the customer involved. 
4. Provide the amount. 
5. Under Expenses column, enter Accounts Receivable and provide the customer's name under Customer job. 
6. Click Save &Close.   

Learn more about this process by viewing this article: Give your customer a credit or refund in QuickBooks Desktop for Windows.

Stay around if you need further assistance or have additional questions. We'll be here always to help. 

This means you owe the customer money.

To get the balance to 0.00, issue a refund check and use your AR account as the account.

Or, if the amount won't be refunded, then enter an invoice for the amount and use the credit balance to pay the invoice.