1/ We are not able to add a product to the cart on your site. Please check product pages (shows 404 page) and your permalinks settings.
2/ “deactivated the theme” – does it means that you have checked the situation when default WooCommerce theme – Storefront is activated?
Provide us with a screenshot or video of the correct work.
You can use Lightshot screenshot or Gyazo tool to make screenshot and share the link here.
3/ Please provide temporary wp-admin and FTP access.
Create an account via Dashboard (Users > Add new) with administrator role http://prntscr.com/s3rc9m > provide us with username and password via the Private Content area http://prntscr.com/s5mao7 You can use any email for it.
If you do not know how to create FTP contact with your hosting provider, they will help you.
One standard license is valid only for 1 project. Running multiple projects on a single license is a copyright violation.