public static int Authenticate(string accountNumber = "", string password = "")
        {
            if (accountNumber != "" && password != "")
            {
                var availability = IsAccountExists(accountNumber);

                if (availability)
                {
                    var responsePassword = AlexaService.GetPassword(accountNumber);

                    if (responsePassword.Equals(password))
                    {
                        return(0);
                    }

                    return(-1);
                }

                return(-2);
            }

            return(-3);
        }