diff --git a/payment/src/main/java/org/killbill/billing/payment/api/DefaultPaymentApi.java b/payment/src/main/java/org/killbill/billing/payment/api/DefaultPaymentApi.java
index d73faad..ac0702a 100644
--- a/payment/src/main/java/org/killbill/billing/payment/api/DefaultPaymentApi.java
+++ b/payment/src/main/java/org/killbill/billing/payment/api/DefaultPaymentApi.java
@@ -462,7 +462,6 @@ public class DefaultPaymentApi extends DefaultApiBase implements PaymentApi {
checkNotNullParameter(currency, "currency");
}
checkNotNullParameter(paymentId, "paymentId");
- checkNotNullParameter(paymentTransactionExternalKey, "paymentTransactionExternalKey");
checkNotNullParameter(properties, "plugin properties");
final String transactionType = TransactionType.REFUND.name();
@@ -717,7 +716,6 @@ public class DefaultPaymentApi extends DefaultApiBase implements PaymentApi {
public Payment createChargebackReversal(final Account account, final UUID paymentId, final String paymentTransactionExternalKey, final CallContext callContext) throws PaymentApiException {
checkNotNullParameter(account, "account");
checkNotNullParameter(paymentId, "paymentId");
- checkNotNullParameter(paymentTransactionExternalKey, "paymentTransactionExternalKey");
final String transactionType = TransactionType.CHARGEBACK.name();
Payment payment = null;
@@ -756,7 +754,6 @@ public class DefaultPaymentApi extends DefaultApiBase implements PaymentApi {
checkNotNullParameter(account, "account");
checkNotNullParameter(paymentId, "paymentId");
- checkNotNullParameter(paymentTransactionExternalKey, "paymentTransactionExternalKey");
final String transactionType = TransactionType.CHARGEBACK.name();
Payment payment = null;
