private function processPaidBills(array $bills)
 {
     //When a bill is paid update the status on the local record and the connected sub charge (if there is one)
     foreach ($bills as $bill) {
         $existingPayment = $this->paymentRepository->getPaymentBySourceId($bill['id']);
         if ($existingPayment) {
             if ($bill['paid_at']) {
                 $paymentDate = new Carbon($bill['paid_at']);
             } else {
                 $paymentDate = new Carbon();
             }
             $this->paymentRepository->markPaymentPaid($existingPayment->id, $paymentDate);
         } else {
             \Log::info("GoCardless Webhook received for unknown payment: " . $bill['id']);
         }
     }
 }