@Emma2411 Forget that- Airbnb will never back you on paying for an entire new set and I'm sure the guests certainly won't agree to pay, I mean they've already denied that they did the damage.
You'll be lucky if Airbnb gives you $200.
It's hard to tell what the table is made of- some kind of resin? If so, I'd just scrape out the burnt part, use some type of filler, and paint it to match the rest of the table. It'll never look perfect again, but so it goes. Or look online-you might be able to get replacement slats from the company.
If it's wood, you could just replace that board.
It would be a good idea to put some kind of trivets or a ceramic tile on that table to put hot pots down on.