Object won't get destroyed

I have several cubes which on collsion should dissapear. And then add points onto the a scroll view text prefab. But the problem is the cubes do not disseappear on trigger collision. Instead it spams the first location regardless enter several times in the scrollview Heres the scripts.

Code (CSharp):

1. using System.Collections;
2. using System.Collections.Generic;
3. using UnityEngine;
4. using UnityEngine.UI;
5. public class LandmarkController : MonoBehaviour
6. {
7.     public LandmarksData[] ld;
8.  
9.     public GameObject itemPrefab;
10.     public GameObject content;
11.     public GameObject addedItem;
12.  
13.     public Animator menuAnim;
14.  
15.     public void AddItemToList(GameObject go)
16.     {
17.         addedItem = Instantiate (itemPrefab);
18.         addedItem.transform.SetParent (content.transform);
19.         addedItem.transform.localPosition = Vector3.zero;
20.         addedItem.transform.localScale = Vector3.one;
21.  
22.         if (go.name.Contains ("Campsite"))
23.         {
24.             addedItem.GetComponentInChildren<Text> ().text = ld [0].landmarkName;
25.         }
26.         else if(go.name.Contains("TwinPeaks"))
27.         {
28.             addedItem.GetComponentInChildren<Text> ().text = ld [1].landmarkName;
29.  
30.         }
31.         else if(go.name.Contains("FallenOne"))
32.         {
33.             addedItem.GetComponentInChildren<Text> ().text = ld [2].landmarkName;
34.  
35.         }
36.         else if(go.name.Contains("Obilisks"))
37.         {
38.             addedItem.GetComponentInChildren<Text> ().text = ld [3].landmarkName;
39.  
40.         }
41.         else if(go.name.Contains("Mine"))
42.         {
43.             addedItem.GetComponentInChildren<Text> ().text = ld [4].landmarkName;
44.  
45.         }
46.     }
47.  

 

Code (CSharp):

1. using System.Collections;
2. using System.Collections.Generic;
3. using UnityEngine;
4.  
5. public class LandmarkVisited : MonoBehaviour
6. {
7.  
8.     public LandmarkController lc;
9.  
10.     // Use this for initialization
11.     void Start ()
12.     {
13.         GameObject lcgo = GameObject.Find ("LandmarkController");
14.         lc = lcgo.GetComponent<LandmarkController> ();
15.     }
16.    
17.     // Update is called once per frame
18.     void OnTriggerEnter (Collider col)
19.     {
20.         lc.AddItemToList (gameObject);  
21.     }
22. }
23.  

Code (CSharp):

1. using System.Collections;
2. using System.Collections.Generic;
3. using UnityEngine;
4.  
5. public class LandmarkCollider : MonoBehaviour
6. {
7.  
8.     public int scoreValue = 100;
9.     private AudioSource source;
10.     [SerializeField] private AudioClip clip;
11.  
12.     // Use this for initialization
13.     void Start () {
14.        
15.     }
16.    
17.     void OnTrigger(Collider col)
18.     {
19.         Debug.Log ("You've visited the" + gameObject.name);
20.         source = col.GetComponent<AudioSource> ();
21.         source.PlayOneShot (clip);
22.         ScoreController.score += scoreValue;
23.         Destroy (gameObject);
24.     }
25. }
26.  

Code (CSharp):

1. using System.Collections;
2. using System.Collections.Generic;
3. using UnityEngine;
4.  
5. [System.Serializable]
6. public class LandmarksData
7. {
8.     public string landmarkName;
9.  
10. }
11.