Customer says their credit card was charged twice and showed proof. Our Payments only showed one transaction. Both Customers was using a Cash App Credit card.

I understand the impact of any delay in resolving this double charges, @d-soule.

We've received reports about the double charge on your customer's credit card. Rest assured, our Payments Support is working on resolving this on-going issue. 

I'd recommend contacting our Merchant Services Care Team. This way, they'll be able to verify the issue regarding the double charge. Also, they can add you to the affected user's list. 

Here's how to reach out to them:

1. Go to Contact Payments Support.
2. Get the phone number from your chosen QuickBooks Online with Payments & Merchant Service Center.

You'll receive an email notification once updates are available.

The Community will always have your back if you need anything else in running your business in QuickBooks Online. Wishing you and your business continued success. 

@d-soule, here is a thread that has the same issue.  It says that Intuit is aware of it and working on it.  

https://quickbooks.intuit.com/learn-support/en-us/payments/customer-support-is-not-only-non-existant...