How to set boundaries in enemy 2D movement?

I adapted this code a little from gamesplus james tutorial. I got it a little bit working. I want the enemy to change direction if it hits a wall. In this case, I am using if transform.position.y > some number.... because I dont want my enemy to detect wall collision. It kinda works but I think waiting for timeBetweenMoveCounter to reach zero everytime, it misses the timing to change direction. I also don't want it to read the code reverse direction like 100 times per second. This runs from void update. How do I arrange this?

Code (CSharp):

1.  
2.     private float timeBetweenMove = 1;
3.     private float timeBetweenMoveCounter;
4.     private float timeToMove = 2;
5.     private float timeToMoveCounter;
6.  
7.     public void RandomMovement()
8.     {
9.         if (IsAlive)
10.         {
11.             if (isPatrolling)
12.             {
13.                 timeToMoveCounter -= Time.deltaTime;
14.                 MyRigidbody.velocity = Direction;
15.  
16.                 if (timeToMoveCounter < 0f)
17.                 {
18.                     isPatrolling = false;
19.                     timeBetweenMoveCounter = Random.Range(timeBetweenMove * 0.75f, timeBetweenMove * 1.25f);
20.                 }
21.             }
22.             else
23.             {
24.                 timeBetweenMoveCounter -= Time.deltaTime;
25.                 MyRigidbody.velocity = Vector2.zero;
26.  
27.                 if (timeBetweenMoveCounter < 0f)
28.                 {
29.                     isPatrolling = true;
30.                     timeToMoveCounter = Random.Range(timeToMove * 0.75f, timeBetweenMove * 1.25f);
31.  
32.                     Direction = new Vector2(Random.Range(-1f, 1f), Random.Range(-1f, 1f) * MoveSpeed).normalized;
33.  
34.                     if (transform.position.y > 6.5f)
35.                     {
36.                         Debug.Log("max y");
37.                         Direction = new Vector2(0f, -2f);
38.                     }
39.                     else if (transform.position.y < -10)
40.                     {
41.                         Debug.Log("mix y");
42.                     }
43.                 }
44.             }
45.         }
46.     }

 

Its really actually easy to solve but i just wanna see your ideas how you would set this up. You dont really need to have advance knowledge of c#