When confronted with an unpleasant outcome, my clients sometimes jump to wild assumptions. Often they are perplexed why certain events occur (or do not) in a negotiation. It is common to assume that the partner is uninformed or just doesn't get it, however I recommend a different tact - maybe you do not get them. Decisions are made in a generally rational construct. Assuming that successfully communicated your plan (a big assumption!), it is likely that you do not know what rubric your partner is using to evaluate your proposal. I find that a good follow up strategy is to ask how you can help them look good. Ask them what metrics they are evaluated against. Ask what metrics their boss is evaluated against. Then strive to provide them the best objective value AND the best professional value. Let me know how this works for you