The Canadian immigration officer answered the wrong question. How to re-enter the country?

It depends on the seriousness of the case, that is, whether the immigration officer thinks that you deliberately lied to get a visa.

If not, go to the Canadian embassy where you used to live, explain clearly the facts and reasons why the content of the question is inconsistent with reality, and then try to apply.

But in the latter case, when you are refused a visa, you may also be banned from setting foot in Canada for a certain period of time. If you really have something to hide or have a recognized reason to land in Canada urgently, you can try to appeal.