How to deal with continued harassment via covert narcs solicitor.

Thanks to my coach, you and Danas video I left my narc and haven't gone back. I've had huge realisations about all my past relationships, how I've ignored red flags and skills to move forward. My issue now is with my ex narc making large financial claims against me via a solicitor and not knowing how to respond. Do I ignore, do I go into detail defending myself, do I tell him to take me to court so I can defend my self with rational, fact and logic? I do t know the best way to answer their letters if at all. We have one property together and dealing with another that do need to be resolved but he is trying to go after more of my properties and money.... I've spent £2,000 so far answering letters via a solicitor and got no where. So need a change of tack but don't know what it is. I would like 121 coaching on this if possible or I can give more detail if needed for a video? Many thanks again.