A well-written rebuttal letter can decrease your likelihood of being sued, serve as evidence in a lawsuit or administrative hearing and alert the other party to evidence they haven't considered. If there's a lot of money at stake, it's a wise idea to hire an attorney, who might address things you haven't considered. But if you need to respond to a simple issue, you may be able to write the letter yourself.
Your rebuttal letter should generally go to the person who sent it, but not always. If there's an attorney involved, for example, you might be legally prohibited from contacting the attorney's client directly. You'll also need to ensure that you copy any third parties. For example, if you're embroiled in an unemployment dispute and receive a letter from your former employee, you might send copies to the employee's lawyer, your human resources department and any third parties involved in the case, such as your state's unemployment office.
If you're trying to avoid a lawsuit or communicating the details of an incident to a third party, you need to provide specific, relevant supporting evidence. Attach documentation if you have it. For example, if you're accused by an employee of firing her for her religion, you might attach the employee's discipline record evidencing her history of stealing. If you have to rebut a claim that you sold defective merchandise, you might include a photo of the merchandise or communication with the customer indicating she was initially happy with the item. Consider the level and detail of your argument and whether you need an attorney.
A letter that rambles on for pages compromises your message. Instead, remain succinct and to the point. Avoid giving out new information or too many details, because this may be used against you. For example, if you fired an employee after she took a religious sabbatical and are subsequently accused of religious discrimination, don't mention the fact that the employee took a religious sabbatical. Instead, just emphasize that she took unauthorized time off off work.
If you're embroiled in a heated dispute, you might be tempted to launch allegations against the other party. Doing so, however, only complicates the issue and won't relieve you of legal liability. If your allegations are untrue and you share them with a third party, you could even be sued for defamation. Stick to the facts, because name-calling will only make you look bad if you end up in court.