As others have suggested, in order to communicate effectively, you have to tailor your message to your audience. Dumb it down, break it down, shorten it, order questions from most to least important or most to least relevant to the recipient, or just badger them relentlessly with follow ups until you have the information you need and talk shit about them behind their back to any competent coworkers you have.

Regardless, they’re not going to just magically change, so it’s up to you to do something different if you want a different result than you’re getting now.