Hi, Mathieu,

Sorry for the delayed response, our support team is cut in half due to COVID-19 infestations. That’s why our response time has increased.

I'm afraid, at the moment there's no feature for refunding Customers in Amelia.

Therefore, refunds should be proceeded manually through the payment system. 

You can suggest that as a feature request here, or check if this request was already submitted and vote for it. 

Please let us know if you have any other questions.

Best Regards.