PlayerPrefs not save my unlock button (Levels lock/unlock)

Hello, I have a problem adding buttons to prefab. I have several levels that are currently locked. The level buttons are locked with another button that on click open PopUp. In a PopUp is another button where on click unlock selected level (or sets the button to inactive). The problem is that Prefab doesn't save my button as inactive and every time I open it the "Locked Button" is active. Who can help me? Thanks everyone!

My code: public class UnlockLevel : MonoBehaviour {

     public List<bool> unlocked;
     public List<GameObject> LevelButton;
 
     int i;
 
     public void Unlock(int level)
     {
         
         LevelButton[i++].gameObject.SetActive(false);
 
         PlayerPrefs.GetInt("Levels",i);
     }
 
     public void EnterLevel(int level)
     {
         if (unlocked[level] == true)
         {
             PlayerPrefs.SetInt("Levels", i);
         }
     }
     
 }