Fatal error

Hello, just updated to the recent Woocommerce verision and cant access my webiste anymore. I get this error

Fatal error: Uncaught Error: Call to undefined function WC() in /hsphere/local/home/banken/boostamig.se/wp-content/plugins/wc-fields-factory/includes/wcff-product-fields.php:85 Stack trace: #0 /hsphere/local/home/banken/boostamig.se/wp-includes/class-wp-hook.php(286): Wcff_ProductFields->registerHooks('') #1 /hsphere/local/home/banken/boostamig.se/wp-includes/class-wp-hook.php(310): WP_Hook->apply_filters(NULL, Array) #2 /hsphere/local/home/banken/boostamig.se/wp-includes/plugin.php(453): WP_Hook->do_action(Array) #3 /hsphere/local/home/banken/boostamig.se/wp-settings.php(450): do_action('init') #4 /hsphere/local/home/banken/boostamig.se/wp-config.php(86): require_once('/hsphere/local/...') #5 /hsphere/local/home/banken/boostamig.se/wp-load.php(37): require_once('/hsphere/local/...') #6 /hsphere/local/home/banken/boostamig.se/wp-blog-header.php(13): require_once('/hsphere/local/...') #7 /hsphere/local/home/banken/boostamig.se/index.php(17): require('/hsphere/local/...') #8 {main} thrown in /hsphere/local/home/banken/boostamig.se/wp-content/plugins/wc-fields-factory/includes/wcff-product-fields.php on line 85

How to solve this?
I cant even access wp-admin backend.
Guessing there is something wrong tieh the fields-factory plugin. But how can it be problem just by and update of Woocommerce?

Thanks