You haven’t properly output them. You’ve closed the PHP tags after this:
), $atts));?>
But, if you want to output a PHP variable you need to open them again, otherwise the text will just be interpreted as HTML. You also need to explicitly echo it. So, for $catheading as an example, you need to output it like this:
<h3><?php echo $catheading; ?></h3>
Also, using extract() is considered bad practice, because it obscures where variables are coming from. You should omit it and just use the $atts array to access the values:
<h3><?php echo $atts['catheading']; ?></h3>