Struggling with Unity 5 GetComponent: Null reference

Hi, I have read a lot of the posts here and none of them are facing my issue. usually this null reference is caused by either accessing a parent when you are not supposed to or the component simply is not attached...Let me start by explaining my hierarchy, specifically what i'm trying to access.

I have a cube with no mesh renderer or collider and it has a door mesh with colliders inside it. the point of the cube is to change the rotation axis of the door therefore the "Rotations script" called doorscript is on the parent of the mesh that I will be raycasting.

Everything works up until it tries to access the script and its function. although mono did suggest the script name when i wrote it.

Here is the problematic line that unity is complaining about

 hit.collider.transform.parent.GetComponent<doorscript>().changedoorstate();

and my code is :

 using UnityEngine;
 using System.Collections;
 
 public class interactScript : MonoBehaviour {
 
     public float interactdistance = 5f;
 
     void Update () {
     if (Input.GetKeyDown(KeyCode.E)){
             Ray ray = new Ray(transform.position,transform.forward);
             RaycastHit hit; 
 
             if(Physics.Raycast(ray, out hit, interactdistance)){
                 if(hit.collider.CompareTag("door")){
                     Debug.Log("Hit Door");
                     hit.collider.transform.parent.GetComponent<doorscript>().changedoorstate();
                 }
             }
         }
     }
 }

 

I have been having these issues non stop when using GetComponent in unity 5 so much that I'd rather just not use it at all :( please can someone help me understand why is is giving me a null reference exception like

NullReferenceException: Object reference not set to an instance of an object interactScript.Update () (at Assets/interactScript.cs:16)