Delete and Update statements in Sqlite not working

I am using SqlitePCL on a windows phone 8.1 application, I have the queries select and insert working but for some reason the delete and update are not working

Here are my codes:

Select Statement:

public static itemPassword[] AllGetItemPassword()
        {
            var db = App.conn;
            int numbofPass = 0;
            itemPassword[] itmpass = null;
            try
            {
                using (var statement = db.Prepare("SELECT nameWeb, username, password, link FROM Passwords"))
                {
                    while (statement.Step() == SQLiteResult.ROW)
                    {
                        numbofPass++;
                    }
                }
            }
            catch
            {

            }

Insert Statement:

    public void insertToDB(String usernameWeb, String userusername, String userpassword, String userlink)
    {
        var db = App.conn;

        try
        {
            using (var pass = db.Prepare("INSERT INTO Passwords (nameWeb, username, password, link) VALUES (?,?,?,?)"))
            {
                pass.Bind(1, usernameWeb);
                pass.Bind(2, "Username: " + userusername);
                pass.Bind(3, "Password: " + userpassword);
                pass.Bind(4, "Link: " + userlink);
                pass.Step();
            }
        }
        catch
        {
        }

And now the not working codes:

Delete statement:

 public static void DeleteRecord12(string webname, string username , string password, string link)
        {
            var db = App.conn;
            try
            {
                using (var pass = db.Prepare("DELETE FROM Passwords WHERE webname = ? AND username = ? AND password = ? AND link = ?"))
                {
                    pass.Bind(1, webname);
                    pass.Bind(2, username);
                    pass.Bind(3, password);
                    pass.Bind(4, link);
                    pass.Step();
                }
            }
            catch (Exception ex)
            {
                ex.GetType();
            }
        }

Update statement:

public void UpdateRecord(string webname, string username, string password, string link,string Newwebname, string Newusername, string Newpassword, string Newlink)
        {
            var db = App.conn;
            try
            {
                using (var pass = db.Prepare("UPDATE Passwords SET webname = ?, username = ?, password = ?, link = ? WHERE webname = ? AND username = ? AND password = ? AND link = ?"))
                {
                    pass.Bind(1, Newwebname);
                    pass.Bind(2, Newusername);
                    pass.Bind(3, Newpassword);
                    pass.Bind(4, Newlink);
                    pass.Bind(5, webname);
                    pass.Bind(6, username);
                    pass.Bind(7, password);
                    pass.Bind(8, link);
                    pass.Step();
                }
            }
            catch (Exception ex)
            {
                ex.GetType();
            }
        }