Please try to replace:
update_post_meta( $post_id, 'figure_sugsubject_repeatable_fields', $new );
with:
add_post_meta( $post_id, 'figure_sugsubject_repeatable_fields', $new );
to add more values related to the figure_sugsubject_repeatable_fields
meta key.
You should also consider using filter_input()
instead of $_POST
.