"The father works every day."
Translation:Hana ka makua kāne i nā lā a pau.
Were you doing it on a phone, where there could have been some synch issue?
Did you file a bug report? It's true that an individual reply to those is unlikely.
You could post in the troubleshooting forum: https://forum.duolingo.com/topic/647
If there's anybody that knows what to do about the issue, that's the place to find them. I suspect that just repeating the lessons will probably be the quickest way to return to level 4.