I'm going to sound a little crazy, but I'd hire a lawyer.
the reason I say this is because if your beloved roses were not "own root roses" then they more than likely not salvageable and here's why. Most rose growers use the root stock of highly disease and pest resistant varieties and then graft on the rose variety they sell them as (that's why they have that extra thick "ball" at the base of the plant). Experts tell us to prune any suckers from below the graft point because you'll only get spindly canes and crappy little roses from them. So if your roofer's cut them down to the rootstock, removing the graft point, essentially they removed your entire rose and it will never come back as the rose you once had. All that's left of your roses are what every variety they used to graft too.
If you want to learn more about "own root roses" check out heirloom roses online. I buy mine from them and they are wonderful.
My heart goes out to you! I baby my roses and would probably end up in jail if anyone ever did this to me. Good Luck!
Valerie