Sparsebundle is reported to be 16mb but actually empty
Sparse disk images grow and shrink and your 16 MB is about the size of a totally empty container.

sudo ls -laR /path/to/mount_point


If there are no files, you will need to restore a backup copy of the sparse disk image or see if a commercial data recovery solution is possible on the storage where you stored the image.

By design, that "image" grows and shrinks in a destructive manner - so you can't expect to perform the "undelete" option that exists for moments of time when you delete a file from traditional spinning hard drive storage media or simple flash based USB drives/SD card type storage.

A sparse image is more like an SSD in that data recovery is not an option and backups are far more important.