i want to get the full list of my google contacts on a JSON file, but im only getting the last value on my contacts.

What should i change? or what is the problem here?

function contactsJSON() {

  var contactsjson = {}
  var myContacts = ContactsApp.getContactGroup('System Group: My Contacts').getContacts();
  for (var i = 0; i < myContacts.length; i++) {

    var id = myContacts[i].getId();
    var name = myContacts[i].getFullName();

    var emailsobj = myContacts[i].getEmails();
    var email = {}
    for (var j = 0; j < emailsobj.length; j++) {
      email[emailsobj[j].getAddress().toLowerCase()] = 1;
    };

    var phonesobj = myContacts[i].getPhones();
    var phone = {}
    for (var j = 0; j < phonesobj.length; j++) {
      phone[phonesobj[j].getPhoneNumber().replace(/[_)(\s.-]/g, '')] = 1;

    };

    for (var j = 0; j < id.length; j++) {
      contactsjson = { id: id, name: name, phone: phone, email: email };
    }
  }

  contactsjson = JSON.stringify(contactsjson);
  contactsjson = JSON.parse(contactsjson);
  Logger.log(contactsjson);
  return contactsjson;
}

Hope you can help me,

Federico.