Rozumiesz - I have a question on Polish language.

Dzień dobry!
I'm new on here. I'm learning Polish and I'd like to ask a question.
I am not sure how to answer the following question. Am I correct?

***
Don't you understand? - Yes, I understand.
Don't you understand? - No, I don't understand.

And this is my choice.
Nie rozumiesz? - Nie, ja rozumiem. or Tak, ja rozumiem.
Nie rozumiesz? - Nie, nie rozumiem.
***

Could someone please explain to me?
Thank you in advance for the answer :)

It should be like this:

Nie rozumiesz ? Nie, rozumiem,
Nie rozumiesz ? Tak, nie rozumiem.

My English teacher told me, they ( English speakers ) don't have double negations.
But in Polish we have.

Don't you understand? - Yes, I understand.
Don't you understand? - No, I don't understand.

And this is my choice.
Nie rozumiesz? - Nie, ja rozumiem. - this is fine. Probably it should be written: Nie. Ja rozumiem.
or Tak, ja rozumiem. It should only go as: Tak.(...) Ja rozumiem.

Nie rozumiesz? - Nie, nie rozumiem. - ok here

I understood! Thank you very much :)

Sometimes, to sound funny or ironic, people use Czech: Ne hozumim.

Rozumiesz? - rozumiem
Rozumiesz? - nie rozumiem
Nie rozumiesz? - nie, nie rozumiem / nie rozumiem
Nie rozumiesz? - rozumiem
But: nie nie, rozumiem means rozumiem

Yes, it looks funny in writing when one comma changes the meaning. But in speaking you use a different stress and pausing, so it is obvious what you want to convey.

It could be funny and absolutely Polish could be confusing:
Rozumiesz, tak? Nie, nie rozumiem.

That`s Anglisized Polish. In real Polish this part of the utterance would sound: Tak, nie rozumiem.

I've been using "nie, nie rozumiem" thousands of times in Poland and I'm sure it's still being used this way. "Tak, nie rozumiem" may be even more confusing, even though logically correct. Anyway, native Poles would clearly understand both versions without dwelling on that.

Exactly!! I only pointed to a prevailing tendency in the language which I use myself as a native Poless. :):):)