Consider diffusing the situation by using love and humor.
Clearly describe the disagreement and explain what you want done to resolve it.
Avoid accusations and threats, particularly in a first letter. (Generally, the intent is to strive to resolve the problem, not simply disagree.) It is important to keep your cool and to remain professional at all times.
Remember to remain courteous, despite the way you may feel.
Keep the tone respectful.
Be clear, direct, and concise.
Address your letter to a specific person, if possible, not just the company or organization in general.
If the problem remains unresolved, you may wish to state clearly in a later letter what action you will take, but only if you are prepared to follow through.
Disagreement Letter Tips
Express your concerns or anger in a constructive, yet assertive way.
State the problem and explain what you want the reader to do about it.
Strive to resolve the problem through explanation and negotiation before going to the expense of litigation. This letter can be used to correct factual errors and misunderstandings in an attempt to resolve the conflict.
State the issue clearly; explain why you disagree with the other person's point of you, with a bill received or other financial matter, or with a proposed course of action; and make your recommendation.
Work to build and maintain goodwill and trust throughout the correspondence.