Fatal Error after Update of Contact form 7

Fatal error: Call to undefined function wpcf7_add_form_tag() in /homepages/32/d570411631/htdocs/clickandbuilds/DarshanaFotografieNeu/wp-content/plugins/contact-form-7-dynamic-text-extension/contact-form-7-dynamic-text-extension.php on line 39

Hey,

i need your guys help with this issue! I did the following:
i backed up my files, updated WordPress to the current version and then started updating the plugins. finally updating contact-form-7 crashed my website and is preventing me from logging in. the only message i get when i try to get to the wp-admin log in page is the above fatal error.

who can help?

thx,

moby

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