Urgent failure

Hi,
I have been trying to contact you by email as well, my request is really urgent for my business…
Since I updated last version of html email woocommerce, I cannot access woocommerce templates and it seems it caused another issue…when I try to place an order and I click to finalize on page “command” I have a message with Internal Server Error…
If not working with 2.7.3, I really want to restore previous version that worked fine…
Please help,
Thank you

The page I need help with: [log in to see the link]