Missing pdf files

-- HikaShop version -- : 6.3.0
-- Joomla version -- : 6.0.3
-- PHP version -- : 8.3
-- Browser(s) name and version -- : latest
-- Error-message(debug-mod must be tuned on) -- : latest

Hello I have the following case. I create a product and put a download pdf file, at the section above the pictures. After saving the product, it can downoad from frontend. The exactly path is for default - media/com_hikashop/upload/safe. There is a .htaccess file in this directory. But for some reasons all of that folder media/com_hikashop/upload/safe is empty, and the links description at every product are broken. What must be the reason for disapearing of the files from that folder. How can I restore it. I search the name of the file in all web site directory, but there is no such file. I search even in .trash folder but it is empty too. I understand probably too late, because backup from one yaer ago is with empty folder too. My question is how that files are dissapear from that folder, and the links broken.