I used to have 8 blogspots with my Blogger account and one fine day, all are gone.
Emailed Blogger, they checked and apologize for the "deletion" and returned 3 of my blogs. The reason why they return 3 (out of 8) blogs is because I only stated the URLs for the 3 blogs - lol, they didn't even bother to check and return all my blogs in my account.
I've recently migrated from Blogger to WordPress. It's simply a much better blogging software to use. Also, it's best to host your blog on your own hosting. You can use the FTP function in Blogger to do that. Even if you remain at blogspot, always do backups.