If the hotel is booked online, but the price has actually increased, is it calculated according to the price booked online or according to the increased price?

The price is legally fixed, but sometimes you can't help it if the offer price changes.

Just like Joyo made a mistake in the price in the past, and then it went back on its word, there was nothing consumers could do.

I suggest you communicate with them, whether you can pay according to the pre-purchased price, or what compensation method you have.