Update free calls documentation

README.md

@@ -144,18 +144,19 @@ If you want to use the free calls you will need to pass these arguments to the `
 
 ```python    
 free_call_auth_token_bin = "f2548d27ffd319b9c05918eeac15ebab934e5cfcd68e1ec3db2b92765",
-free_call_token_expiry_block = 172800
+free_call_token_expiry_block = 172800,
+email = "[email protected]" # which using in AI marketplace account
 ```
 
 You can receive these for a given service from the [Dapp](https://beta.singularitynet.io/)
 
 Creating a service client with free calls included would look like this:
 ```python
 service_client = snet_sdk.create_service_client(org_id="26072b8b6a0e448180f8c0e702ab6d2f", 
-                                                service_id="Exampleservice",
-                                                group_name="default_group",
+                                                service_id="Exampleservice"
                                                 free_call_auth_token_bin="f2548d27ffd319b9c05918eeac15ebab934e5cfcd68e1ec3db2b92765",
-                                                free_call_token_expiry_block=172800)
+                                                free_call_token_expiry_block=172800,
+                                                email="[email protected]")
 ```
 
 ### Paid call