HIGHEND Theme problem

I have some problem with my website using highend theme & need to fix .
1. “Cash on delivery ” is disappeared from checkout page ,while it’s enable.
2-in product pages , when adding discount to products price , the old price & new price are over wrap & then should choose smaller font to solve the problem & it’s too small .

I can see that there is 2 outdated template in status page :
HighendWP/woocommerce/cart/cart.php version 3.3.0 is out of date. The core version is 3.4.0,
&
HighendWP/woocommerce/single-product/add-to-cart/variable.php version 3.0.0 is out of date. The core version is 3.4.1,

Also style.css have 8 error & this error message exist in editor page for style.css
There are 8 errors which must be fixed before you can update this file.

I need help to fix these problems
my website url is sigmadigitals.com