Using the object.Equals() method for a custom class

I’ve created my own class Contact to hold a bunch of variables on a series of gameobjects, and a series of the Contacts are being held in a list.
I’d ideally like to be able to use the built in methods like list.Contains() for the sake of convenience. From what I’ve been able to find on the .Contains() method, it uses a method named Equals() in the class which has to be overridden.

I’m attempting to return true from .Equals() when the string “id” is the same for the compared Contacts.
What I have so far is as follows:

public class Contact : object
{
    public GameObject game_obj;
    public string id;
    public float level;
    public float health;

    public float distance = 0;
    public Vector3 direction = new Vector3(0, 0, 0);

    public bool more_stuff = false;

    //constructors
    public Contact(GameObject go)
    {
        game_obj = go;
        id = go.name;
        level = go.GetComponent<NpcManager>().level;
        health = go.GetComponent<NpcManager>().health;
    }

    //comparator
    public override bool Equals(Contact other)
    {
        Debug.Log("Called it.");
        //check for null vals and compare types
        if (other == null || GetType() != other.GetType())
        {
            return false;
        }
        return (id == other.id);
    }

    public override int GetHashCode()
    {
        return base.GetHashCode();
    }

}

The problem I’m having is that when I try to override the Equals method, unity throws an error saying that Contact.Equals(Contact) cannot override because object.Equals(object) is not a method.

The articles I’ve used: object.equals() and list.contains()

Check out this article. The problem is you need to override the System.Object Equals method and then implement your own Equals method for your object like this:

public override bool Equals(System.Object obj)
{
    if (obj == null)
        return false;

    Contact c = obj as Contact ;
    if ((System.Object)c == null)
        return false;

    return id == c.id;
}

public bool Equals(Contact c)
{
    if ((object)c == null)
        return false;

    return c == c.id;
}