Installation removed plesk packages

Hi,

I was trying to install a package on my server, but I didn't see that it was going to delete plesk, there is the log :

(Lecture de la base de données... 134661 fichiers et répertoires déjà installés.)
Suppression de psa-vpn (12.0.18-ubuntu14.04.build1200140610.21) ...
Suppression de plesk-management-node (12.0.18-ubuntu14.04.build1200140610.21) ...
Suppression de psa-mnemo (4.2.6-ubuntu14.04.build1200150706.15) ...
Suppression de psa-turba (4.2.7-ubuntu14.04.build1200150706.15) ......

Installation removed plesk packages