There is a room in front of the hotel 10, but it is not allowed to check in in advance. Can I complain?

Of course. According to the hotel rules and regulations, the hotel has a room before 10, but it is not allowed to check in early, because the normal check-in time is after 12, but if you check in before 10, you need to add half a day's room charge, and every customer has the right to complain. So the hotel has a room before 10, but you can complain if you don't check in early.