Under normal circumstances you will get a kit that contains a lot of more or less things (e.g. your certification on paper, a pin, etc ). This kit also contains a paper form where you are asked if everything was OK and if not you can report this.
But, are you sure that the code snippet contains an error ?
The other aspect, please be careful, you are not allowed to expose in public details about the exam and because you acknowledge this (not expose details) before you start the exam.