Unity Ads Reward the player with tips (text) and not coins, stars ...

Hello, I am a beginner, thank you for your help.
Rewarded Ads work perfectly but I need to reward the player with tips, not coins or anything like that. My code works in the player but not on android device. What is wrong?
I am using Unity 2018.2.17f1
Thank you

Code (CSharp):

1.  
2. using System.Collections;
3. using UnityEngine;
4. using UnityEngine.Monetization;
5. using UnityEngine.UI;
6.  
7. public class RewardedAdsPlacement : MonoBehaviour
8. {
9.     public Text Tips;
10.     public Text Tips01;
11.  
12.     public string placementId = "rewardedVideo";
13.  
14.     public void ShowAd()
15.     {
16.         StartCoroutine(WaitForAd());
17.     }
18.  
19.     IEnumerator WaitForAd()
20.     {
21.         while (!Monetization.IsReady(placementId))
22.         {
23.             yield return null;
24.         }
25.  
26.         ShowAdPlacementContent ad = null;
27.         ad = Monetization.GetPlacementContent(placementId) as ShowAdPlacementContent;
28.  
29.         if (ad != null)
30.         {
31.             ad.Show(AdFinished);
32.         }
33.     }
34.  
35.     void AdFinished(ShowResult result)
36.     {
37.         if (result == ShowResult.Finished)
38.         {
39.             // Reward the player
40.             Tips.GetComponent<Text>().text = "Tips : " + Tips01.GetComponent<Text>().text;
41.         }
42.     }
43.     void Update()
44.     {
45.        
46.     }
47.  
48. }
49.  

 

This is the code

Code (CSharp):

1.    
2. using System.Collections;
3. using System.Collections.Generic;
4. using UnityEngine;
5. using UnityEngine.Advertisements;
6. using UnityEngine.Analytics;
7.  
8. public class Ads: MonoBehaviour
9. {
10. public void ShowRewardedAd()
11.     {
12.         const string RewardedPlacementId = "rewardedVideo";
13.  
14.  
15.         if (!Advertisement.IsReady(RewardedPlacementId))
16.         {
17.             Debug.Log(string.Format("Ads not ready for placement '{0}'", RewardedPlacementId));
18.             return;
19.         }
20.  
21.         var options = new ShowOptions { resultCallback = HandleShowResult };
22.         Advertisement.Show(RewardedPlacementId, options);
23.  
24.     }
25.  
26.  
27.     private void HandleShowResult(ShowResult result)
28.     {
29.         switch (result)
30.         {
31.             case ShowResult.Finished:
32.                 Debug.Log("The ad was successfully shown.");
33.  
34.                //Your redward. Coins += 100.
35.  
36.                 PlayerPrefs.SetInt("Coin", Coins);
37.  
38.                 AnalyticsEvent.Custom("RedwardAdsComplete"); //Add event is complete in Unity Analytics.
39.  
40.                 //
41.                 // YOUR CODE TO REWARD THE GAMER
42.                 // Give coins etc.
43.                 break;
44.             case ShowResult.Skipped:
45.                 Debug.Log("The ad was skipped before reaching the end.");
46.                 break;
47.             case ShowResult.Failed:
48.                 Debug.LogError("The ad failed to be shown.");
49.                 break;
50.         }
51.     }