Max Spawning Obejcts

I'm making a FPS in c# (iv just started scripting) and I have a script that spawns objects at 3 different locations every 5 seconds. I have implanted some code that prevents more than 5 objects to spawn but for some reason this is not working. This is my code:

 public class RandomBadGuySpawn : MonoBehaviour {
     public GameObject spawnPrefab;
     public float spawnTime = 5;
     public Transform[] spawnPoints;
     int maxBadGuys = 5;
     public int currentBadGuys = 0;
    
 
     // Use this for initialization
     void Start () {
         InvokeRepeating("Spawn", spawnTime, spawnTime); //The time between each Milk Spawned so 5sec then spawn and wait another 5
     }
     
     // Update is called once per frame
     void Update () {
     
     }
 
     public void Spawn()
     {
         if (currentBadGuys >= maxBadGuys)
             return;
         Debug.Log("Max BadGuys");
         int spwanPointIndex = Random.Range(0, spawnPoints.Length);
         Instantiate(spawnPrefab, spawnPoints[spwanPointIndex].position, spawnPoints[spwanPointIndex].rotation);
 
     }
 }
 

I'm also wondering if it is possible to stop objects spawning after you destroy the objects and after a certain amount of seconds they spawn back? Thanks for the help if any, much appreciated!