I wrote "there isn't a radio in the house". It should have been accepted but was not. Unless I am missing something, grammatically it is correct.
This is probably a very stupid analysis, but i think in your way of saying it , there's more emphasis on existence vs anti-existence; In Duos way of saying it, the emphasis is on tangibility.
Shouldn't "I don't have a radio at home" be accepted as well?
I think it wasn't accepted because there was no Korean word for "I" included in the sentence.
Could you also say : "The house has no radio." ?
In your sentence, "house" is the topic of the sentence, so it would be written as "집은 라도오가 없어요." The meaning doesn't change of course, it's just a grammatical difference.
House is not a person so it sounds weird