unity: AdMob interstitial ads are not displayed after publishing to playstore

I created a Unity game, first I add an AdMob interstitial ad script to the game object and then I test it on my main camera when I test on my mobile before publishing. It worked as ads in real time and, by mistake, I pressed it and I gained 0.3, so I think the new ad unit I placed in my game and then I published my game. But the ads are not shown in real time. No errors were found in AdMob, but 147 ad requests are shown in AdMob and the ads are not seen when the first scene of my game is opened.

Here is my interstitial ad script code:

using UnityEngine;

using System.Collections;
using GoogleMobileAds.Api;

public class AdmobScript: MonoBehaviour
{
Interstitial interstitial private;

Private empty RequestInterstitial ()
{
                string adUnitId = "ca-app-pub-3129337025883034/9036322 ***";
                                    string adUnitId = "INSERT_IOS_INTERSTITIAL_AD_UNIT_ID_HERE";
                                    string adUnitId = "unexpected_platform";
                // Create an interstitial.
this.interstitial = new InterstitialAd (adUnitId);
// Load an interstitial ad.
this.interstitial.LoadAd (this.CreateAdRequest ());
}

// Return an ad request
Private AdRequest CreateAdRequest ()
{
return new AdRequest.Builder (). Build ();
}

Private ShowInterstitial ()
{
if (interstitial.IsLoaded ())
{
interstitial.Show ();
}
}

home empty public ()
{
RequestInterstitial ();
}

Null update ()
{
ShowInterstitial ();
}

}