I had the same experience...on my birthday this year! The phone suddenly was stuck in a reboot cycle, and I HAD BACKUP SOFTWARE. I called Verizon (LG Ally) and was told I needed to do a factory reset. I did not understand (this is my first smartphone) that I would lose all data...and I too was ANGRY afterwards that I wasn't warned, so that I could backup my data BEFORE the reset, since I had an app installed already!!!
So, this is where it goes south...it turns out my app, much to my surprise and chagrin, only backed up my TEXTS. I lost my browser bookmarks, call logs, all of it. The bookmarks loss hurt the worst!
Since then, I have been much more careful and found an app that backs up everything, and I do them regularly. I also have an antivirus app since I've found that's important too. Smartphones are a lot like a small computer, really.
The thing that makes me the most upset is that the techs with the providers say NOTHING about losing all data....are they unaware? Reading from a script and not allowed to deviate from it? I don't know...don't really care. When they walk you through fixes, you should be informed as to what's happening. Period.
Lesson: Backup your data, often and regularly. I backup mine into 2 diff locations, for security. Get an antivirus app...do your homework before deciding which apps to use for these functions. MOST OF ALL...when you are on the phone with tech support for your phone, ASK QUESTIONS. I held my tongue, and ohhh how I wish I had asked more questions. Things WILL happen...my error was simply a data loop outta control. WHY that took a factory reset I'm uncertain. BACKUP BEFORE CALLING TECH SUPPORT. This way everyone's time is saved, and there's no egg on your face. =)