I am a startup lawyer and mediator, and my advice in situations where there is not an agreement in place that adequately resolves a conflict is to recommend mediation. If "kitchen table" negotiations have failed to resolve the issue, before you spend tens of thousands of dollars on litigation, the best route is to attempt face-to-face mediation with a neutral facilitator. It is usually less expensive than litigation and generally stays more positive and has a more mutually agreeable outcome. Feel free to contact me if you want more background on what mediation entails.