All I can suggest to you is to save your precious energy. Why would a person want to engage with combative energy that is not interested in lending an ear or taking an interest in your attempts at trying to communicate. I have been in that position before as I was in a relationship with a man that treated me the exact same way, thank goodness I saw the light and loved myself enough to release myself from that person or definite hell would have been my future. It’s funny, for a while now I’ve been investing time in myself and learning how to love myself and what it actually is to love myself and when you start to align yourself with who you authentically are, you begin to make healthy decisions for yourself to the point where if something is not healthy for you, there is going to be some cutting out whether it’s a person, a situation or anything negative that doesn’t fit into your new understanding of who exactly it is that you are. It doesn’t really matter how this person is connected to you, if their energy is combative and unwilling then leave them to themselves and protect your own energy by disengaging. If it it necessary that you communicate with this person then do it through a trusted friend or a lawyer or somebody external to yourself to relay the information or you could write it in a letter. If a person doesn’t want to hear it then you must back down. If they are being combative then save your time and energy and theirs too. I apologize if this sounds harsh but everyone has their boundaries and if one doesn’t want to listen then boundaries must be respected. Let it go.