Admob not working i not find a solution

hi want to implement admob, i follow the examples,the is very simple and . In the log of the unity editor is showing dummy ad, but in the device not apear.
I see a lot of people ask the same and noone respond . This is the last for publish my app and cant do because of this.
The code is attached to my camera to test it (i tried wait , not wait, use testdevice, not use test device, etc, etc, etc)

using UnityEngine;
using System.Collections;
using GoogleMobileAds.Api;
using UnityEngine.SocialPlatforms;
using GooglePlayGames;
using GooglePlayGames.BasicApi;

public class ControladorMenu : MonoBehaviour {
private BannerView banner;

// Use this for initialization
void Start()
{
    RequestBanner();
    Process();
    banner.Show();

}

// Update is called once per frame
void Update () {
	if (Input.GetKeyDown (KeyCode.Escape)) 
		Application.Quit ();
}

private void RequestBanner()
{
    string adUnitId = "ca-app-pub-xxxxxxxxxxxxxxxxx/xxxxxxxxx";
    // Initialize an InterstitialAd.
    this.banner = new BannerView(adUnitId, AdSize.Banner, AdPosition.Center);
    // Create an empty ad request.
    AdRequest request = new AdRequest.Builder()
    .AddTestDevice(AdRequest.TestDeviceSimulator)       // Simulator.
    .AddTestDevice(SystemInfo.deviceUniqueIdentifier)  // My test device.
    .Build();
    banner.LoadAd(request);
}

IEnumerator Process()
{

    //Wait 1 second
    yield return StartCoroutine(Wait(5.0f));
    //Do process stuff
}

IEnumerator Wait(float seconds)
{
    yield return new WaitForSeconds(seconds);
}

Sorry, but i find response to all problems but this code is so simple that make me crazy.
Thank you in advance.

Hi, i find the solution.
I had not completed the billing nformation on the ADMOB page. IN the page says that no ad show anything before complete that information.
Bye!