Meaning of じゃ無いんじゃないかって


I'm not sure how to understand/translate the phrase 「じゃ無いんじゃないかって」

> それはあんまり良いことじゃ無いんじゃないかって

For more context, previous sentences translated to:

> You always had those (headphones) on when you were walking right? Even
> during the times you didn't use them, they were definitely in your bag.

I understand that it's talking about how that something is not very good?  
But I'm thrown off by that phrase  

