diff --git a/lib/grpc_reflection/service/builder.ex b/lib/grpc_reflection/service/builder.ex
index 3278e0a..44ba834 100644
--- a/lib/grpc_reflection/service/builder.ex
+++ b/lib/grpc_reflection/service/builder.ex
@@ -108,7 +108,7 @@ defmodule GrpcReflection.Service.Builder do
        when extension_range != [] do
     unencoded_extension_payload = %Google.Protobuf.FileDescriptorProto{
       name: extension_file,
-      package: Util.package_from_name(symbol),
+      package: Util.get_package(symbol),
       dependency: [symbol <> ".proto"],
       syntax: Util.get_syntax(mod)
     }
@@ -144,7 +144,7 @@ defmodule GrpcReflection.Service.Builder do
   defp process_extensions(_, _, _, _), do: {:ignore, {nil, nil}}
 
   defp process_common(name, module, descriptor) do
-    package = Util.package_from_name(name)
+    package = Util.get_package(name)
 
     dependencies =
       descriptor
diff --git a/lib/grpc_reflection/service/builder/util.ex b/lib/grpc_reflection/service/builder/util.ex
index cac8264..424e412 100644
--- a/lib/grpc_reflection/service/builder/util.ex
+++ b/lib/grpc_reflection/service/builder/util.ex
@@ -7,13 +7,20 @@ defmodule GrpcReflection.Service.Builder.Util do
 
   @type_message Map.fetch!(Google.Protobuf.FieldDescriptorProto.Type.mapping(), :TYPE_MESSAGE)
 
-  def package_from_name(service_name) do
-    service_name
-    |> String.split(".")
-    |> Enum.reverse()
-    |> then(fn [_ | rest] -> rest end)
-    |> Enum.reverse()
-    |> Enum.join(".")
+  def get_package(symbol) do
+    parent_symbol = symbol |> String.split(".") |> Enum.slice(0..-2) |> Enum.join(".")
+
+    try do
+      parent_module = convert_symbol_to_module(parent_symbol)
+
+      if function_exported?(parent_module, :descriptor, 0) do
+        get_package(parent_symbol)
+      else
+        parent_symbol
+      end
+    rescue
+      _ -> parent_symbol
+    end
   end
 
   def upcase_first(<<first::utf8, rest::binary>>), do: String.upcase(<<first::utf8>>) <> rest
@@ -95,14 +102,8 @@ defmodule GrpcReflection.Service.Builder.Util do
       name -> name
     end)
     |> String.split(".")
-    |> Enum.reverse()
-    |> then(fn
-      [m | segments] -> [m | Enum.map(segments, &upcase_first/1)]
-    end)
-    |> Enum.reverse()
-    |> Enum.join(".")
-    |> then(fn name -> "Elixir." <> name end)
-    |> String.to_existing_atom()
+    |> Enum.map(&upcase_first/1)
+    |> Module.safe_concat()
   end
 
   def is_message_descriptor?(%Google.Protobuf.FieldDescriptorProto{type: @type_message}),
diff --git a/test/builder/util_test.exs b/test/builder/util_test.exs
index 3115f22..d37ce61 100644
--- a/test/builder/util_test.exs
+++ b/test/builder/util_test.exs
@@ -10,8 +10,15 @@ defmodule GrpcReflection.Service.Builder.UtilTest do
   end
 
   describe "common utils" do
-    test "get package from module name" do
-      assert "a.b" == Util.package_from_name("a.b.CService")
+    test "get package from module" do
+      assert "testserviceV3" ==
+               Util.get_package("testserviceV3.TestRequest")
+
+      assert "testserviceV3" ==
+               Util.get_package("testserviceV3.TestRequest.Payload.Location")
+
+      assert "testserviceV3" ==
+               Util.get_package("testserviceV3.TestService")
     end
 
     test "upcase_first" do
@@ -21,6 +28,17 @@ defmodule GrpcReflection.Service.Builder.UtilTest do
     test "downcase_first" do
       assert "hello" == Util.downcase_first("Hello")
     end
+
+    test "convert symbol to module succeed" do
+      assert TestserviceV3.TestRequest ==
+               Util.convert_symbol_to_module("testserviceV3.TestRequest")
+    end
+
+    test "convert symbol to module fail" do
+      assert_raise ArgumentError, fn ->
+        Util.convert_symbol_to_module("testservice.TestRequest.Payload.Location")
+      end
+    end
   end
 
   describe "utils for dealing with proto2 only" do