How much notice did you give them?
Do you know if there was pressure on places?
There wasn't or you just don't know?
The question here really is how much risk you want to take.
Whichever way you look at this, you are liable. You agreed a place and didn't agree suitable cancellation rights.
However, to claim the full price from you they would have to show that they suffered loss - in this instance that they could not sell your places to others and there was pressure on places.
If there was pressure on places then that is a double edged sword because they will have held a place for you but you could argue they could have given it to reserves and ask them to prove they have tried.
The reality is that it is quite unlikely they would sue for a sum of this amount anyway.
But they could and you do need to be aware of the risk
The other alternative is that you offer them their lost profits in full and final settlement of the claim which would be far less than the sum of the contract.
Can I clarify anything for you?
Yes, that is of no issue to liability.