bug reports/support

Hello there! I just enchanted my Iron Sword twice from level 2 to 4 but it did not apply, all though in the enchanting table it says it is level 4. Is there anyone that has a fix for this?

well i have my report closed and i still don't understand what does messenger wanting to say Report 1. TITLE: Tower defense gives minecraft crash that happens very rarely Answered questions and responses: Everything except the 2 last part as i accidently clicked the submit button...