Trouble in calculating angle.

Hi.. I am a novice in Unity. I have a setup where in a scene there are multiple objects(Say balloons).The task is to navigate around the scene and click on the balloon. And here I need to calculate the angle between the heading direction and the object position. My game has a FPS Controller with 4 cameras, covering the 360 degree view of the scene. My calculated angles were coming correct without the FPS controller. However when I used the FPS controller the angle calculated are coming wrong. I think this is happening because the FPS controller itself can rotate.

 private float calculateActualAngle(){
         Vector2 reference = new Vector2 (0f, 1f) - new Vector2 (0f, 0f);
         Vector2 balloonVector = new Vector2 (foundObject.transform.position.x, foundObject.transform.position.z) - new Vector2 (gameObject.transform.position.x,gameObject.transform.position.z);
             
         float balloonAngle = Vector2.Angle (reference,balloonVector);
         if (foundObject.transform.position.x < gameObject.transform.position.x)
             barrelAngle = -barrelAngle;
         Debug.Log ("The actual angle calculated is " + balloonAngle);
 
         return balloonAngle;
 
     }

  

Here gameObject is a FPSController with 4 cameras as children which covers the front left right and backside views. foundObject is obtained as follos in update() block.

  void Update () {
             MeshRenderer foundObjectMeshRenderer;
             foreach(CB cb in componentCameraCB){
                 if(cb.objectHit()){
                     foundObject = cb.returnHitObject();
                     foundObjectMeshRenderer = foundObject.GetComponentInChildren<MeshRenderer>();
                     foundObjectMeshRenderer.material = foundObjectSkin;
     
                     foundObject.layer = foundLayer;
                     foundObject.GetComponentInChildren<Transform>().gameObject.layer = foundLayer;
     
                     for(int j = 0;j< 12;j++){
                         if(foundObject.transform.position == balloons[j].transform.position){
                             orderOfSelection.Add(balloons[j].name);
                         }
                     }
     
                     actualAngles.Add(calculateActualAngle());
     
                     count = count + 1;
                     setEnableCompass(true);
                     behaviour.enabled = false;
                 }
             }
 

Please let me know where I am going wrong?