Re: I received a duplicate payment. The original payment was made via credit card. Now they have ...
Thanks for posting in the Community, @gmains. I'd be glad to lend a hand with refunding a duplicate payment.
The following article contains the necessary steps for refunding a credit card payment in QuickBooks Online (QBO): How to void or refund a credit card payment. This resource also contains additional insight into this process, such as processing times.
If your customer is wanting the ACH payment refunded, please be aware that ACH refunds aren't allowed and cash or check must be used. For information on recording a refund, I recommend the following article: Record a customer refund.
Should you have any additional questions about refunds in QBO, I'm just a quick post away. Cheering you to continued success.