A cell phone contract is often called the "Terms of Service Agreement" or "Terms and Conditions of Service." It is a legally binding agreement between the user and the cell phone company covering charges, billing, and other terms of service.
If the phone plan is purchased through a retailer or agent, there may be an additional Terms and Conditions agreement, with additional cancellation fees.
The Terms and Conditions document is binding and overrides any verbal promises or representations made to you by a sales person. However, the Terms and Conditions documents may not include the complete contract terms if it refers to other documents, such as brochures and marketing materials that describe the service plans, making those materials part of the "contract."
Many consumers are charged very steep penalty fees for canceling unsatisfactory cell phone service. The majority of cell phone providers do not pro-rate the early termination charge based on the length of time remaining in the contract. Consumers are advised to read all documents carefully prior to purchase and get all spoken promises in writing. A copy of the Terms and Conditions and related marketing materials and brochures that describe the plan should be retained for future reference.