killbill-aplcache

diff --git a/payment/src/main/java/com/ning/billing/payment/api/DefaultPaymentApi.java b/payment/src/main/java/com/ning/billing/payment/api/DefaultPaymentApi.java
index 30c4c03..adc4669 100644
--- a/payment/src/main/java/com/ning/billing/payment/api/DefaultPaymentApi.java
+++ b/payment/src/main/java/com/ning/billing/payment/api/DefaultPaymentApi.java
@@ -65,7 +65,12 @@ public class DefaultPaymentApi implements PaymentApi {
 
         if (accountKey != null) {
             final Account account = accountUserApi.getAccountByKey(accountKey);
-            return getPaymentProviderPlugin(account);
+            if (account != null) {
+                return getPaymentProviderPlugin(account);
+            }
+            else {
+                throw new IllegalArgumentException("Did not find account with accountKey " + accountKey);
+            }
         }
 
         return pluginRegistry.getPlugin(paymentProviderName);

diff --git a/payment/src/main/java/com/ning/billing/payment/provider/PaymentProviderPluginRegistry.java b/payment/src/main/java/com/ning/billing/payment/provider/PaymentProviderPluginRegistry.java
index f7778d8..fc9c149 100644
--- a/payment/src/main/java/com/ning/billing/payment/provider/PaymentProviderPluginRegistry.java
+++ b/payment/src/main/java/com/ning/billing/payment/provider/PaymentProviderPluginRegistry.java
@@ -38,6 +38,12 @@ public class PaymentProviderPluginRegistry {
     }
 
     public PaymentProviderPlugin getPlugin(String name) {
-        return pluginsByName.get(StringUtils.defaultIfEmpty(name, defaultPlugin).toLowerCase());
+        PaymentProviderPlugin plugin = pluginsByName.get(StringUtils.defaultIfEmpty(name, defaultPlugin).toLowerCase());
+
+        if (plugin == null) {
+            throw new IllegalArgumentException("No payment provider plugin is configured for " + name);
+        }
+
+        return plugin;
     }
 }