I finally got my contacts phone numbers back. But since I imported three times the .vcf file on the account page, I erased all and imported again the working file (fossify export). Now I have every number one time WITH phone number, great. But the phone now refuses to sync: error 404 !?!
uh, wait, actually it is working if I do it with the sync button (bottom on the image above)! Periodic and manual sync from the menu is also working now.