public static function paymentFailed(Purchase $purchase, $amount)
    {
        Log::info("Payment failed ({$purchase->purchaseId})");

        $purchase->buyer->sendEmail(
            'Your payment has failed',
            'emails.item.failed',
            [
                'total' => $amount,
                'item_name' => $purchase->item->name,
                'payment_id' => $purchase->purchaseId,
            ]
        );
    }