How to send data from Android to Django

Question

I can't find the problem with POST data, I have django app deployed on Heroku and android app that needs to send data to it when user finishes game. When I tested data saving without POST method (hardcoded values) it worked. Can anybody tell me where is the problem in my code?

urls.py

url(r'^scorepost/', 'scorepost'),

view.py

@csrf_exempt
def scorepost(request):
    if request.method == 'POST':        
        email = string(request.POST['email'])
        difficulty = string(request.POST['difficulty'])
        time = string(request.POST['time'])
        moves = string(request.POST['moves'])
        score = string(request.POST['score'])

        user = CustomUser.objects.get(email=email)
        Highscore.objects.create(user_id = user.id, difficulty = difficulty, time = time, moves = moves, score = score)
        return HttpResponse("Score saved")

    return HttpResponse("Score not saved")

android

HttpClient httpclient = new DefaultHttpClient();
HttpPost httppost = new HttpPost("http://testdjangoandroid.herokuapp.com/scorepost/");

try {
    List<NameValuePair> pairs = new ArrayList<NameValuePair>(5);
    pairs.add(new BasicNameValuePair("email", user_email));
    pairs.add(new BasicNameValuePair("difficulty", Integer.toString(difficulty)));
    pairs.add(new BasicNameValuePair("time", Long.toString(totalTime)));
    pairs.add(new BasicNameValuePair("moves", Integer.toString(totalMoves)));
    pairs.add(new BasicNameValuePair("score", Long.toString(totalScore)));

    httppost.setEntity(new UrlEncodedFormEntity(pairs));

    httpclient.execute(httppost);