What’s wrong with get_term_link

I have a code witch diplay list of sub-subcategories form subcategory 8, but href is “www.mypage.com/?taxonomy=&term=” only this part of this code is wrong, as U can see this link is broken. What’s wrong?

<?php if ( is_category('8') ) {
	       	foreach (get_the_category('cat_ID=8') as $category); ?>

		<?php
$cat = get_query_var('cat');
$categories=get_categories('child_of='.$cat);
if ($categories) {
  foreach($categories as $term) {
    echo '<p>' . $title . '<a href="' . get_term_link( $term->term_id, $taxonomy ) . '" title="' . sprintf( __( "View all posts in %s" ), $term->name ) . '" ' . '>' . $term->name.'</a> has ' . $term->count . ' post(s). </p> ';
    echo 'Category description is:' . $term->description;
  }
}
?>

 <?php } else	<?php if ( is_category('8') ) {
	       	foreach (get_the_category('cat_ID=8') as $category); ?>

		<?php
$cat = get_query_var('cat');
$categories=get_categories('child_of='.$cat);
if ($categories) {
  foreach($categories as $term) {
    echo '<p>' . $title . '<a href="' . get_term_link( $term->term_id, $taxonomy ) . '" title="' . sprintf( __( "View all posts in %s" ), $term->name ) . '" ' . '>' . $term->name.'</a> has ' . $term->count . ' post(s). </p> ';
    echo 'Category description is:' . $term->description;
  }
}
?>

 <?php } else