diff --git a/src/InvoiceManager.php b/src/InvoiceManager.php
index 464c7b1..cf0dc71 100644
--- a/src/InvoiceManager.php
+++ b/src/InvoiceManager.php
@@ -52,7 +52,7 @@ public function createInvoice(OrderInterface $order): Invoice
 		$invoiceItem = $this->invoiceRepository->getByOrder($order);
 		if ($invoiceItem !== []) {
 			/** @var Invoice $invoice */
-			$invoice = $invoiceItem;
+			$invoice = $invoiceItem[0];
 			$invoice->setPrice($order->getPrice());
 		} else {
 			assert($order instanceof Order);