AutoCall how to make a call at specified time

Question

I am trying to build an app which lets users to make calls at specified time to a selected phone number.

Here is the Code-

   protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_final);
    Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
    setSupportActionBar(toolbar);

    tvPhoneNumber = (TextView) findViewById(R.id.tvPhoneNumber);

    tvTime = (TextView) findViewById(R.id.tvTime);

    buttonExitApp = (Button) findViewById(R.id.buttonExitApp);

    buttonExitApp.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            Intent it = new Intent(Intent.ACTION_CALL);
            it.setData(Uri.parse("tel:" + tvPhoneNumber.getText().toString()));
            Calendar cal = Calendar.getInstance().getInstance();
            cal.add(Calendar.MINUTE, 1);
            PendingIntent sender = PendingIntent.getBroadcast(getApplicationContext(), 1612, it, PendingIntent.FLAG_UPDATE_CURRENT);
            AlarmManager am = (AlarmManager) getSystemService(ALARM_SERVICE);
            am.set(AlarmManager.RTC_WAKEUP, cal.getTimeInMillis(), sender);
            // startActivity(it);
     //                finish();
        }
    });


    SharedPreferences sp = getSharedPreferences("MyPref", Context.MODE_PRIVATE);

    String phoneNumber = sp.getString("PhoneNumber", "No Date Received");

    String time = sp.getString("TIME", "No Date Received");

    tvPhoneNumber.setText(phoneNumber);

    tvTime.setText(time);


}

Here tvPhoneNumber refers to the phone number, and tvTimerefers to the specified time.

Just for demo I tried using Calender and added 1 minute to it and then trying to set alarm. But it not working.

I also wan to convert tvTimeto millisecs.

I don't know where I am doing wrong. After one minute nothing happens.