use the_content instead of the_excerpt

is there a way to display the_content of the full single page product description, because the excerpt does not use html formatting. There are no line breaks and it looks horrible.

I'd like to use the full content of the single product as the descriptions on the product page.

If this is not possible, then at least can you please help me lengthen the excerpt length of my product descriptions on the product page?
Yes I found the forum post and codex post, I have a functions.php file in my child theme template folder which looks exactly like this
function new_excerpt_length($length) {
return 80;
add_filter('excerpt_length', 'new_excerpt_length');
but it does nothing.

Ive tried using smaller numbers to make sure im not missing something, but nothing changes it.
Even if I directly hack marketpress.php or formatting.php, nothing changes.
Why is this?
Are the product descriptions not from the_excerpt?
How can I figure this out, please it's driving me crazy.