Giving partial refunds
Unfortunately, giving partial refunds to customers is not possible on Gumroad. Maybe in the future it will be possible. We'll let you know if we change this.
If you need to issue a partial refund to your customer you can:
A) Refund them 100% through the customers tab. Here's how.
B) Reach out to your customer and ask them for their PayPal, Venmo, or Square Cash ID. You can then pay them the difference.