I was told that I was late for check-out time at the hotel and I was charged an extension fee, but I do not want to pay this because I was not informed of the time.

In general, the check-out time is indicated on the reservation confirmation form, explained in writing or orally at the time of check-in, or written in the information file provided in the room. First, please double-check the information on your reservation confirmation form. Then, explain your particular situation to the hotel staff; for example, you received no such explanation or written information, or that you were informed of an incorrect time.