Freeze Gameobject's position on collision

Im making a car AI where it goes to the enemy. When it collides with a game object other than the ground, I want it to freeze it's position and rotation (just stop the car.) Here is the code I have so far:

     void OnCollisionEnter (Collision col)
     {
 
         if (col.gameObject.name == "Ground") {
             
             //Do nothing
 
         } else {
 
             // freeze car here
             print ("froze");
 
         }
 
     }

This script is attached to the car, the car has a rigid body and box collider. I have tried these lines of code to stop the car

 GetComponent<Rigidbody>().GetComponent<Rigidbody>().constraints = RigidbodyConstraints.FreezePositionX | RigidbodyConstraints.FreezePositionZ | RigidbodyConstraints.FreezePositionY;
 
 transform.position = Vector3.zero;
 
 theRigidbody.velocity = Vector3.zero;
 
 this.GetComponent<Rigidbody>().useGravity = false;