First show the roofing company the damaged plant. If you have a picture of it blooming will help for them to understand why you wouldn't recommend them to anyone. They may offer to purchase one for you but I doubt it.

Make certain the soil around the plant is carefully loosened, maybe with a fork, if it is compacted. Your baby may come back next spring but the branches will be very tender. You will want to provide some sort of protection for the branches until they become woody.

If the roofing company will replace the plant this is the time to purchase it. Planting it now will allow roots to start growing before freeze.

It would be nice if we could wack on the roofers for destroying your peony , but some of those types just don't seem to have any appreciation for anything green and growing. But don't give up on your peony yet,follow maifleurs advice. the damage may set it back a year or two but hopefully it will come again from its roots. It may take a year or two to develop enough old wood to bloom again. Good luck!

Tree peonies generally have loads of dormant "buds" on the lower parts of the stems and these should sprout now that there is nothing else left, so I think it will come back in time.

It may also sprout from below ground level. Note that many tree peonies are grafted on herbaceous penoy roots and so you should watch for herbaecous penoy shoots and remove them.

I realise that many people don't appreciate plants, but severely damaging and possibly killing a plant that will cost several hundred dollars to replace is not acceptable and you should pursue them for a replacement. People here can advise on reliable sources for large healthy tree peonies.