During my stay, the hotel held a meeting to raise the room rate, and I was not allowed to stay. How can I protect my rights?

It's no use. Hotel price increases are usually clearly marked. Book as many days as you need to stay next time, otherwise the hotel has the right not to let you stay longer. This is normal. If you suddenly change your mind and want to stay longer, what will the hotel do? I wish I had a room for you.

Look at the problem from different angles. If you make a reservation and the hotel suddenly increases its price, you can defend your rights. Otherwise, move to another place, but I think other hotels will definitely raise prices.