Before the meeting closes, raise your concerns with the chair and suggest that another meeting be arranged.
If you didn't manage this during the meeting, follow up points one-on-one with key influencers you noticed in the meeting and get detailed feedback on their reasons for not accepting outcomes/compromises in the session. This will give you a far deeper insight into whether a follow-up meeting is required and how to structure the next meeting(s) to have a better chance of settled outcomes.