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.

Shouldn't "I don't have a radio at home" be accepted as well?

Could you also say : "The house has no radio." ?

Is the "yo" at the end strictly needed - or is it just for politeness? (I hear "eobseo" a lot in Kpop but never "eobseoyo", so just wondering...)