DK Werefox

I went from having over 500 prims on my property to use, above the ones I already use, , to having 4. The land is only supposed to be used by three people - my group, and I returned all obejects, even my house (sigh) - but it still says there are over 500 prims on my property, but zero objects. I asked around, and was told someone has used scripts to steal my prims. How do I find and fix?