ionic framework bad request when calling web service over 3G

I'm developing iOS app using ionic framework and I have one problem when I try to call web service by using 3G network.

here is my service in UserService:

function getUserStat(user_id){
        var request = $http({ method: "get",
                              url: "http://www.example.com/user.php",
                              params: {
                                action: "stat",
                                user_id:user_id
                            },
                            data: {
                            }
                        });

        return(request.then(handleSuccess, handleError));
    }

function handleError( response ) {

        // The API response from the server should be returned in a
        // nomralized format. However, if the request was not handled by the
        // server (or what not handles properly - ex. server error), then we
        // may have to normalize it on our end, as best we can.
        if (!angular.isObject( response.data ) || !response.data.message) {
            return( $q.reject("An unknown error occurred.") );
        }

        // Otherwise, use expected error message.
        return( $q.reject( response.data.message ) );

    }

    // I transform the successful response, unwrapping the application data
    // from the API response payload.
    function handleSuccess( response ) {
        return( response.data );
    }

the getUserStat() function will return json back.

here is my controller

UserService.getUserStat($scope.user_id).then(function(data){
        alert("Result: " + JSON.stringify(data));
    });

in my control I just show the json.

I build this code to my iPhone and test it over WIFI network, everything work fine. If i update the serverside, UserService.getUserStat in controller will show update. but the problem is when I test it on 3G network, iPhone always show the old json returned from the server (even I change server side data).

any idea to solve this problem?

Thank you

I had a similar problem when I tried to upload a camera photo to my data server.when i tested the app on my local WIFI it worked perfectly but when I tested it outside i noticed it fails to upload the file. eventualy the problem was that since the internet outside is much slower the app moved to another view without finish the upload action.

so for example if your controller looks something like this:

.controller('Ctrl1', function(webService, $scope, $state) {
   UserService.getUserStat($scope.user_id).then(function(data){
       alert("Result: " + JSON.stringify(data));
   });

   $state.go('app.posts');
});

it should be like this:

.controller('Ctrl1', function(webService, $scope, $state) {
   UserService.getUserStat($scope.user_id).then(function(data){
       alert("Result: " + JSON.stringify(data));
   })
   .finally(function() {
       $state.go('app.posts');
   });
});