Sorry to hear that, MadDog. I understand how frustrating this can be.
First and foremost, the TD software itself will never delete any of your data. There simply is no code within the software to do this. Not a tournament file, not a template, nothing. The best you can do is individually delete players, leagues, and/or seasons from your database. And even that comes with warnings and confirmations before the software will do it.
So, having said that, this type of issue is usually attributed to either a confusion as to where the software is saving your data, or the software looking in a different location to find your data. Of course, I cannot say what has happened in your particular situation (it's possible your IT department DID delete your data), but usually data has not been deleted, but has more likely gone missing.
I could go into where the TD stores files by default, or about using/changing the Data Store, but I think the first thing you should do is simply search your hard drive for a Tournament Director file, if you haven't already. Open Windows Explorer, select your C: drive, then enter *.tdt in the Search box (upper right-hand corner) and see what is found. If the data hasn't actually been deleted, it should turn up in the search.