Translation:I have never gone to that part of the country.
"I never have gone to that part of the country" was not accepted. I think it is also correct.
This is just another example of duo's way or the highway. "I have never gone into" and "I have never went into" mean the same thing. Maybe one day duo but in the meantime it's your way.
"Went" is past tense of "to go." "Gone" is the past participle of "to go." With the auxiliary verb "have," one must use the past participle: have gone, are gone, had gone, were gone (but not have went, are went, had went, were went)
I agree that "are went" and "were went" makes no sense but "have went" and "had went" still sound good to me. "I've went there", "I've gone there" and "I've been there" all sound good to me. I'm not saying that the French sentence is wrong, I'm just writing down what I think is the translation in English. My answer might sound odd to you but I think it's correct and would be understood if talking to friends, although it maybe a bit informal. Thanks for your reply.
It looks like you understood the french but had trouble with the English. Your second verb is wrong and we wouldn't use "into" here.
You seemingly don't quite grasp that I'm not here to learn English, I'm here to learn French and if my English is not up to your standard, that does not mean that I cannot speak English. My answer was accepted by Duo, I was only replying to a comment about the English answer that was given by Duo.