If even a microscopic modicum of good faith exists between the parties (i.e., the institution’s lawyers haven’t gotten involved yet), mediation is the way to go before, during, or after the informal period—the earlier the better.
Many people confuse mediation with binding arbitration. In arbitration a third party, sometimes a retired judge, listens to both sides and then issues a binding decision. In contrast, nobody decides anything for anybody else in mediation. The parties involved must agree to mediate, and they must mutually agree on any solutions found. It is simply a discussion facilitated by a professional mediator in a safe environment to get at the real interests (as opposed to positions) of the parties and work out a solution acceptable to all everyone. The beauty of mediation is that it most often aims at repairing relationships as much as it aims at solving the issue at hand. You can walk out of a mediation session with a stronger working relationship with the other party than you ever had before.
Mediation works. Try it if your institution offers it. If it does not offer mediation, check around for a county dispute resolution office somewhere. Lawyers can charge $1,000 or more for a single session, but DRCs, using volunteer mediators, often charge only about $25 a session. Even if you do not succeed, a hearing panel and perhaps a judge down the road will give you credit for trying.
Do NOT turn down an offer from your institution to mediate even if you believe nobody on the other side is operating in good faith. If you do go to court someday, you can bet the judge will get an earful about how uncooperative and unreasonable you have been. Goodness! You even turned down mediation! Go to any mediation you get the chance to participate in and go there with the mindset that you’re going to make something good happen. If nothing does, make sure it’s the other side’s attitude and not yours in the way.