Hello there,

I'm here to help share an option on how to record a non-refundable downpayment in QuickBooks Online (QBO).

QuickBooks doesn't have an option to mark the Accounts Payable (A/P) as billable, what you need to do is create a bill or check for your vendor with the downpayment amount and mark it as billable to link with your customer. And since QBO cannot identify if it's a non-refundable, you can add a note on the memo field instead.

To create a bill, here's how: 

1. Select the Plus icon (+) on the Toolbar.
2. Under Vendors, select Bill.
3. On the Bill page, select a Vendor.
4. Use the fields in the Category details to enter information for the bill including the appropriate Account.
5. Enter the downpayment Amount.
6. Make sure to mark the Billable as check.
7. Select the name of your customer. 
8. Add a note on the Memo field.  
9. Click Save. 

If you'd like to write a check, you can visit this article for the detailed steps: How to write checks. 

Once done, you can now create an invoice to the customer to link the billable bill/check you've created. 

If you need further assistance with the steps, I encourage you to contact our QuickBooks Online Support so they can do a screen-share.

Here's how you can contact our customer support:

1. Sign in to your QuickBooks Online company.
2. Select Help (question mark icon) at the top right.
3. Select Contact us to connect with a live support agent.

That should do it! Fill me in if you have additional questions about recording a downpayment in QBO. Wishing you and your business continued success.