Question about UniverItaly applications

So I recently got a acceptance letter from messina, after registering on the UniversItaly website.
But I also sent an application to both Turin and Pisa. But Pisa is telling me that without sending a pre application on the Univeritaly website I wont have an answer to my application.
I dont wanna withdraw pre application to Messina and then be rejected by Turin and Pisa, can anyone recommend what I can do?