Collision detection – Collider problems

My Sprite is moving against a platform.

[My Sprite is moving against a platform. I have a script and an unusual one (that's what one of the members said). My isGrounded is not by any rayCasting. I had no problem with that, but when I created a platform and jumped against it:
1) It would fall slowly.
2) If I try to move against him, I could move and it would seem that the sprite was flying.
So the question is: How can I stop all my movements, jumping everything, when I collide like this on the platform?
My code is:

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class pScript: MonoBehaviour {
Rigidbody2D public rb;
    [SerializeField]
    Public transformation[] Points;
    [SerializeField]
    public flotation radio;
    [SerializeField]
    LayerMask public layer;
public jump bool;
bool public isgrounded = false;
    [SerializeField]
    public float MoveSpeed;
    [SerializeField ]
    high public float jump
public bool versus right;
animator public animator;
Public object CallfPanel;
Public object CallfText;
public floating movement = 8f;
public Vector3 Dir;
Vector3 public pie;
// Use this for initialization
void Home () {
rb = GetComponent ();
animator = GetComponent ();
CallfPanel = GameObject.Find ("Panel");
CallfText = GameObject.Find ("Text");
}

// The update is called once per frame
null Update () {
RaycastHit hit;
Debug.DrawRay (transform.position, Vector3.right, Color.white, Move);
cake = new Vector3 (200, 300, transform.position.z);
Dir = Vector3.right;
if (jump == true) {
if (Physics.Raycast (tart, Dir, out hit, Move)) {
jump = false;
}
}

horizontal float = Input.GetAxis ("Horizontal");
animator.SetFloat ("speed", Mathf.Abs (horizontal));

isgrounded = isGrounded ();
rb.velocity = new Vector2 (horizontal * MoveSpeed, rb.velocity.y);
if (Input.GetKeyDown (KeyCode.Space)) {
jump = true;
}
if (isgrounded && jump == true) {
isgrounded = false;
rb.velocity = new Vector2 (0, jumpHigh);
}
if (isgrounded == false) {
jump = false;
}
changeDirections ();
}
private bool isGrounded () {

if (rb.velocity.y <= 0) {
foreach (points of transformation into points) {
Collider2D[] collider = Physics2D.OverlapCircleAll (points.position, radio, layer);
for (int i = 0; i < collider.Length; i++) {
                    if (collider [i].gameObject != gameObject) {
                        return true;
                    }

                }

            }

        }return false;
    }
    public void changeDirections(){
        float horizontal = Input.GetAxis("Horizontal");
        Vector3 theScale = transform.localScale;
        if (theScale.x == 1) {
            facingRight = true;
        } else {
            facingRight = false;
        }

        if (horizontal > 0 &&! FacingRight || horizontal <0 && facingRight) {
theScale.x * = -1;
transform.localScale = theScale;
}
}
public void showTextDuration () {
floating life time = 4.0f;
Destroy (CallfPanel, life time);

}
}