half files erased on ftp! Need urgent help!

Hi
one of an admin have erase : all the files on the admin folder, the htaccess and all the files on the roots of the ftp ( wp-config…)

So i copy paste all those files from another website with enfold and set the config.php.
All is now working (access to backoff, all the pages online are ok, dashboard…)

Only 2 things are not working :
1- when i click save setting on enfold setting page it display :
“Saving didnt work! Please reload the page and try again”
2- Page on backoffice won’t open correctly : the rounded timer turn without stopping on avia form.

Can you help on that please, credentials on private