why is it called this?

They didn't solve *every* mystery at the end of the show. I guess it is because a mystery is something you don't understand and all of the stories on that show featured that common element - something that was missing that made it so that all or part of the story didn't make sense of didn't fit together in a logical, coherent whole. All of them were unsolved at the time they aired, and they weren't solved until viewers called in with information - but those updates were given on later broadcasts. Also, some of the mysteries, such as those concerning religion or history or miracles some other phemenomenon based on opinion or believe did not have the potential to be "solved." I don't know if that answers your question.

i dont have ne idea abt this

Well, I guess they are referring to when they are being showed before they show was aired.

When they gave te 'update' segments, it was when the mystery had been solved after they had originally aired the story. Other than that, I think that all of the mysteries really were unsolved.