Someone did my ITR12 income tax return and now wants R6000 for doing it, is that normal?

Unfortunately we cant comment on this matter as it doesn't fall within the arena of tax returns. I can only say that you should collect all written forms of evidence that you have, whether they are emails, letters or even SMSs, and put these together to prove your case should you decide to take legal action. Good luck, I hope it works out!