How to recover my blownup/trolled minecraft server?

So for the past 3 months my friends and I have been building a city in minecraft and put a lot of work, fun, and creativity into our buildings and structures. I'm the owner of the server and have been paying monthly to keep the server up. One day I logged into the server to find out that my entire city had been blown up with lava everywhere. Some person with no consideration for time and work had blown up and trolled my friends and I's world. Is there a way I can restore the server to a save point before it got blown up so everything can be back to normal? Please help because this is very angering and I don't know what to do.

Well, first of all, when I was owner of mc server I always copied my saved world backup to desktop or somewhere else everyday so in case was like yours, but problem is it seems you don't have the server hosted in your pc, this is bad, you need to call your server hoster to back the save up, thats if they made one, so… Really sad this happened to you, I hope you won't give up on server and try to build a better city, also I prefer hosting server in your pc and make save backups everyday, or tell your hoster company to make backups for cases like this.

You can't.

Make a Copy of your world Before you let someone on Your server. Btw its Griefing and Trolling. So a griefer pretty much came on your server and Griefed your world. So yes before you let someone you don't know come on your server its Best to save your world or back your world up Or you can make a copy of it.