You may follow these instructions if you are having trouble with registering for the test on https://www.topik.go.kr/:

<If you are having technical difficulties while logging in>

- In order to make changes during the registration period, go to [마이페이지/My page] then [회원정보수정/Update profile] or [접수정보 입력/Input information]. 

- If the registration period is over, you have to send an email to topikcs@korea.kr or give a call to the test center (02-3668-1331). Make sure to have your application number, identification documents, and other details before contacting. The subject of your email should be: "application number - 개인 정보 변경 요청