> IT28
This is a "Text" that you have created in the list of questions, and it show content on the page, but not when you're editing the text. Please corerct me, if I misunderstood.
> It seems everything was erased on their own!
I read that as: The texts do neither appear when editing the text, nor when viewing the questionnaire?
SoSci Survey will not delete (or modify) contents on its own. Switching translations (not the base language) in survey projects can be an issue, and also importing projects from XML files, but I assume you would have noticed doing such a modification actively.
Before you start and re-create every text, I would like to scrutinize that in detail. I definitely want to know what goes wrong, and why, if anything goes wrong.