I have been an Ombudsman for many years, and I was trained as a mediator at Cardinal Stritch University.
Sometimes is it necessary to go the legal route, but often, a bit of patience and desire for a mutually-agreed outcome is possible. Here are your options:
OMBUDS process: This is a unique opportunity for you to meet with the other party in the following setting: It is private, it is non-binding, nothing is recorded and nothing said during these sessions can be taken to court. So, in this discreet session or two, you are able to honestly and openly hear each other. You get the facilitation of a the Ombuds process to explore ways to meet each other equitably. Do remember, if you are interested in this option, I will reach out to the other party, and if they agree, we will pursue this option. However, if they are not interested, your options would be mediation, or arbitration, or to take legal action. These alternative dispute resolution options are often delivering results that both parties can accept, because they are directly involved in the process. In the legal process, you lay your case before a judge, and then you are at the mercy of the process. You have relinquished much of your options and input.
MEDIATION: Whereas the Ombuds process in informal, the mediation process is formal. The process might include face to face with the other party, or a process with the mediator only, or a mix of the two. If both parties are sincerely seeing a fair outcome, this process can deliver well to hear each other, to understand why there might be a gap in alignment of thinking, and then to collectively seek a best way. As the mediator, I do have a direct hand in designing the communication process as the two parties work towards a solution, but I do not add my impressions and bias to work towards a preferred outcome. I deeply respect both parties to meet each other's needs and to find a solution that both can accept. The only compliment I work for is that I was fair, and that both parties respect me in being unbiased and fair. The success of this process is yours. If you both are sincere, things really look good, but if one party is not striving for mutual success, then no mediator can succeed. We facilitate, we provide opportunity and we design the path to bring our opportunities to express your views, to understand the other party, and to reach consensus.
It is deeply gratifying when you resolve the matter, rather than focus on fighting and venting.