Answer:
Maybe you should try and explain what really happened to the teacher/headmaster. If you calmly and politely (Even if you are very upset internally try to stay calm and not show it externally so that you are portrayed more responsible and trustworthy.) explain the misunderstanding, they might lesson/remove your punishment.
If this doesn't work, talk to a trusted adult (like your parents) and ask them to talk to the teacher/headmaster. It's unfair for you to be punished for something you didn't do, it's not your fault that the table broke. Therefore, you shouldn't be punished for it!