Issue sinatra returning response object instead of json

contact.rb

require "rubygems"
require "sinatra/base"
require 'pony'
require 'yaml'
require 'json'

class Contact < Sinatra::Base

  before do
    p"START LOGGING"
    response.headers["Access-Control-Allow-Origin"] = "*"
    response.headers["Access-Control-Allow-Methods"] = "POST"
    p response.headers.inspect
  end

  # Load the configuration file for the mailserver settings
  conf = YAML.load_file('configuration.yml')

  post '/' do
    content_type :json

    p params.inspect

    if params[:email].empty?
      response[:status] = "error"
      response[:message] = "No email"
      p "json: #{response.to_json}"
      body response.to_json
    elsif params[:mailbody].empty?
      response[:status] = "error"
      response[:message] = "No message?"
      response.to_json
    elsif 
      
      Pony.mail(
          :from => params[:email] + "<" + params[:email] + ">",
          :to => 'geert.theys@gmail.com',
          :subject => params[:email] + " has contacted you",
          :body => params[:mailbody],
          :via => :smtp,
          :via_options => { 
            :address              => conf['smtp'], 
            :port                 => conf['port'], 
            :user_name            => conf ['user_name'],
            :password             => conf ['password'],
            :enable_starttls_auto => true, 
            :authentication       => :plain
          })
        response[:status] = "success"
        response[:message] = "Email sent. We will contact you as soon as possible"
        
        p response.inspect

        response.to_json

      end

  end
end

form.js

// Contact form submission
$(document).ready(function() {

    jQuery("#clickme").click( function() {
        $('body').css('cursor', 'wait');
        var form=$('#contactForm');
        $.ajax({
            type: "POST",
            url: "http://cooldevops_contact.dev/",
            data: form.serialize(),
            dataType: "json",

            success: function(msg) {
                $("#formResponse").removeClass('error');
                $("#formResponse").removeClass('success');
                $("#formResponse").addClass(msg.status);
                $("#formResponse").html(msg.message);

            },
            error: function() {
                $("#formResponse").removeClass('success');
                $("#formResponse").addClass('error');
                $("#formResponse").html("There was an error submitting the form. Please try again.");
            }
        });
        $('body').css('cursor', 'default');
   });
});

log

"START LOGGING"
"{\"Content-Type\"=>nil, \"Access-Control-Allow-Origin\"=>\"*\", \"Access-Control-Allow-Methods\"=>\"POST\"}"
"{\"email\"=>\"\", \"mailbody\"=>\"\"}"
"json: \"#<Sinatra::Response:0x007fed1cec5cc8>\""
127.0.0.1 - - [01/Aug/2014 13:10:55] "POST / " 200 39 0.0079

if params[:email].empty?
  {
    :status => "error",
    :message => "No email",
  }.to_json
elseif ....