Response Data not passed through json

The following script is suppossed to return for me the requests booked and append the data I got through json to html.

function readUsers() {
    //display ajax loader animation
    $( '#ajaxLoadAni' ).fadeIn( 'slow' );

    $.ajax({
        url: 'user_transactions/get_request',
        dataType: 'json',
        success: function( response ) {
            alert(response)
            for( var i in response ) {
                response[ i ].updateLink = updateUrl + '/' + response[ i ].id;
                response[ i ].deleteLink = delUrl + '/' + response[ i ].id;
            }

            //clear old rows
            $( '#records' ).html( '' );

            //append new rows
            $( '#readTemplate' ).render( response ).appendTo( "#records" );

            //hide ajax loader animation here...
            $( '#ajaxLoadAni' ).fadeOut( 'slow' );
        }
    });
} // end readrequest

I am able to get the data from the url but when I alert the response , it is empty , how can I pass the data through the success function?