diff --git a/src/Eth.php b/src/Eth.php
index 9564032..d6c337c 100644
--- a/src/Eth.php
+++ b/src/Eth.php
@@ -365,7 +365,7 @@ class Eth
     public function __call($name, $arguments)
     {
         if (empty($this->provider)) {
-            return;
+            throw new \RuntimeException('Please set provider first.');
         }
 
         $class = explode('\\', get_class());
diff --git a/src/Net.php b/src/Net.php
index 7f4b164..cf74d00 100644
--- a/src/Net.php
+++ b/src/Net.php
@@ -64,7 +64,7 @@ class Net
     public function __call($name, $arguments)
     {
         if (empty($this->provider)) {
-            return;
+            throw new \RuntimeException('Please set provider first.');
         }
 
         $class = explode('\\', get_class());
diff --git a/src/Web3.php b/src/Web3.php
index ef844e0..1d49c9c 100644
--- a/src/Web3.php
+++ b/src/Web3.php
@@ -86,7 +86,7 @@ class Web3
     public function __call($name, $arguments)
     {
         if (empty($this->provider)) {
-            return;
+            throw new \RuntimeException('Please set provider first.');
         }
 
         $class = explode('\\', get_class());