Problem with pause menu/button - It doesn't pause

I'm new to C# and I'm making a game, with a pause menu. I believe time.timeScale is the problem. The button just uses the Toggle function. The pause menu worked before I updated the WaveSpawner script to spawn each wave with different enemies

Pause Menu Script

 public GameObject ui;

 public string menuSceneName = "MainMenu";

 public SceneFader sceneFader;

 public Text roundsText;

 void Update ()
 {
     roundsText.text = PlayerStats.Rounds.ToString();

     if (Input.GetKeyDown(KeyCode.Escape) || Input.GetKeyDown(KeyCode.P))
     {
         Toggle();
     }
 }

 public void Toggle()
 {
     ui.SetActive(!ui.activeSelf);

     if (ui.activeSelf)
     {
         Time.timeScale = 0f;
     }
     else
     {
         Time.timeScale = 1f;
     }
 }

WaveSpawner Script

public static int EnemiesAlive = 0;

public GameOver gameOver;

public Wave[] waves;

public Transform spawnPoint;

public float timeBetweenWaves = 5f; private float countdown = 2f;

public Text waveCountdownText;

private int waveNumber = 0;

void Update () { if (EnemiesAlive > 0) { return; }

  if (countdown <= 0f)
  {
      StartCoroutine(SpawnWave());
      countdown = timeBetweenWaves;
      return;
  }

  countdown -= Time.deltaTime;

  countdown = Mathf.Clamp(countdown, 0f, Mathf.Infinity);

  waveCountdownText.text = string.Format("{0:00.00}", countdown);

  if (gameOver)
  {
      this.enabled = false;
  }

}

IEnumerator SpawnWave () { PlayerStats.Rounds++;

  Wave wave = waves[waveNumber];

  for (int i = 0; i < wave.count; i++)
  {
      SpawnEnemy(wave.enemy);
      yield return new WaitForSeconds(1f / wave.rate);
  }

  waveNumber++;

  if (waveNumber == waves.Length)
  {
      Debug.Log("Level Won!");
      this.enabled = false;
  }

}

void SpawnEnemy(GameObject enemy) { Instantiate(enemy, spawnPoint.position, spawnPoint.rotation); EnemiesAlive++; } }