Hello Javier,
first of all do not delete anything or empty the trash.
It is a bit strange that you found the sparsebundle in the trash it should have been on your desktop.
But never mind, just make sure you do not delete it.
But there should also be a file named 2xxxxxx password do not delete.txt" this file should also be on the desktop. The password is there.
Please let me know if you found it, and then I will give you further instructions,
Rgds
Zsolt