Bonjour Pierre
unfortunately I can't speak any French, but I think I understood most of your message by using an online translation. The free version of PDF Architect can be used for an unlimited time, but it only has limited functionality and can't be used to e.g. edit text. Here is a overview of which features are included in which edition:
https://www.pdfforge.org/pdfarchitect/features
If you'd like to refund and purchase the promotional offer instead, the refund might be faster if you directly contact the sales support at upclick: http://www.upclk.com/contact.aspx (Upclick is our E-commerce partner/reseller for PDF Architect).
Best regards
Robin