Signing on blank papers

Thanks a lot.

Actually, they told me to sign as they want to write something on it for making immigration card and visa.

Now that I have signed, what can I do about it? Should I ask them to give back the paper?

Do I need to complain somewhere? To what extent they can misuse it?

Please go to their office and take it back. Misuse possibilities are endless. You need to focus on taking proactive steps.