Renderer.Material doesn't work on android Build

Hi everyone, my trouble is this:

i made a Maze game with a shop at main menu, there you can buy different skins for the table and the ball. i've created 6 different ones and a default one (7 in total) for scenario and the same for balls. Each one has a button to equip the skin. That button change the material on floor and walls or ball.

On unity editor all works fine, you can switch skins without any trouble, but when i build it and tested with my phone this doesn't work, i press all equip buttons but any change.

I leave my script:

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 using UnityEngine.UI;
 
 public class ChangeTexture : MonoBehaviour
 {
     public GameObject player;
     public GameObject wall;
     public Material material_1;
     public Material material_2;
     public Material material_3;
     public Material material_4;
     public Material material_5;
     public Material material_6;
     public Material material_7;
 
     int materialCase = 0;
 
     public void material1()
     {
         materialCase = 1;
         CambiarMaterial();
     }
 
     public void material2()
     {
         materialCase = 2;
         CambiarMaterial();
     }
 
     public void material3()
     {
         materialCase = 3;
         CambiarMaterial();
     }
 
     public void material4()
     {
         materialCase = 4;
         CambiarMaterial();
     }
 
     public void material5()
     {
         materialCase = 5;
         CambiarMaterial();
     }
 
     public void material6()
     {
         materialCase = 6;
         CambiarMaterial();
     }
 
     public void material7()
     {
         materialCase = 7;
         CambiarMaterial();
     }
 
     public void CambiarMaterial()
     {
         Renderer rend = player.GetComponent<Renderer>();
         Renderer rendd = wall.GetComponent<Renderer>();
         switch (materialCase)
         {
             case 7:
                 rend.material = material_7;
                 rendd.material = material_7;
                 break;
             case 6:
                 rend.material = material_6;
                 rendd.material = material_6;
                 break;
             case 5:
                 rend.material = material_5;
                 rendd.material = material_5;
                 break;
             case 4:
                 rend.material = material_4;
                 rendd.material = material_4;
                 break;
             case 3:
                 rend.material = material_3;
                 rendd.material = material_3;
                 break;
             case 2:
                 rend.material = material_2;
                 rendd.material = material_2;
                 break;
             case 1:
                 rend.material = material_1;
                 rendd.material = material_1;
                 break;
             default:
                 break;
         }
     }
 }

Any idea that why this doesn't work? This is my first game and i'm still learning :(