content underneath contact form

I need to edit some text in an existing multilingual Drupal website. The text is located underneath the contact form.
In search of a way to edit this text, I stumbled upon the Blocks list, where I found the piece of text I wanted to edit. This block is set to show on the contact page.

After editing the Block body and flushing all caches, the changes still don't appear on the site.

My guess is, that I'm looking at the wrong admin section to edit this text, because at the Block editing page, there is only the possibility to edit one language (standard is dutch).

Could someone guide me to the section, where I can edit the content underneath my contact page ? I am an absolute beginner at Drupal.