Hey Gabor, are you saying you deleted it from the dashboard interface? Or you deleted a component or body inside of Fusion 360? If in Fusion 360 it shouldn't be a problem to roll the time line back or ctrl+z to get it back, but if you deleted it from the dashboard I fear that it is gone, as it pops up saying it will be permanently deleted.
Hi Gabor,
Feel free to shoot me a email at nathan.skalsky (AT) Autodesk.com and we'll explore your options if you've deleted your design data that you'd like back.
Thanks!
-Nathan