Where is the error in my bookmark code ?

Below is javascript code to bookmark specific member profiles on my website, when I click the bookmark button it does not bookmark the profile I am asking to be bookmarked.

Link code:

// Bookmark link
                    if($this->logged_in_user != $id) {
                        $bookmarked = get_user_meta($this->logged_in_user, 'erns-bookmarked_profiles', true);
                        $bookmarkedT = false;
                        if(!empty($bookmarked)) {
                            $bookmarked = json_decode($bookmarked, true);
                            if(in_array($id, $bookmarked)) {
                                $bookmarkedT = TRUE;
                            }
                        }
                        if($bookmarkedT) {
                            $display .= '
Remove Bookmark
';
                        } else {
                            $display .= '
Bookmark
';
                        }
                    }
Javescript to write to database to bookmark/unbookmark the profile:
$('.lnk-bookmark').on('click', function (e) {
        e.preventDefault();
        var $lnk = $(this);
        var todo = ($($lnk).hasClass('bmadd') ? 'add' : 'remove');
        var userid = $($lnk).attr('id');
        userid = userid.replace('bm-', '');
        if(!$($lnk).hasClass('disabled')) {
            $($lnk).addClass('disabled');
            $.post(
                ERNSCustom.AdminAjax,
                {
                    'action' : 'erns_profile_bookmark',
                    'todo' : todo,
                    'userid' : userid
                },
                function(response){
                    if(response && response.status=='success') {
                        if(todo == 'add') {
$($lnk).removeClass('bmadd').addClass('mbremove').html('Remove Bookmark');
                        } else {
$($lnk).removeClass('mbremove').addClass('mbadd').html('Bookmark');
                        }
                    }
                    $($lnk).removeClass('disabled');
            }, "json");
        }
    });

The link is suppose to trigger the code to bookmark or unbookmark the individual profiles.

How do I get the code to trigger because it won’t now

Ok…making progress…when I press bookmark, the button changes to “remove bookmark” when I press that the button won’t remove it, meaning the button should go back to “bookmark” and it is not

any ideas why ?