A nice thing to know about iDEAL, is that iDEAL payments can not be refunded by consumers. This is of course possible with PayPal or credit card payments. Some businesses see this a big benefit for iDEAL, but consumers off course see this as a limitation. But with good communication between you and your consumers/customers, this shouldn't be a problem for iDEAL payments. You, as a Mollie user, can refund iDEAL payments via the Mollie dashboard. It's just that consumers can't initiate the refund.