app/controllers/spree/admin/payments_controller_decorator.rb
Spree::Admin::PaymentsController.class_eval do
def mollie_refund
status = MolliePaymentService.new(order: @order, payment: @payment).refund_payment
if status.refunded?
flash[:success] = Spree.t(:refund_successful, scope: 'mollie')
else
flash[:error] = Spree.t(:refund_unsuccessful, scope: 'mollie') + " (#{status.errors.join("\n")})"
end
redirect_to admin_order_payments_path(@order)
end
end