The contract is legal. Contracts made to buy or sell anything illegal are not enforceable. The contract must be made by people who are legally capable. This is called capacity. People who are not legally capable of making contracts are minors - people under the age of 18 unless they are married or the other party can show the contract is fair and reasonable.
Most contracts have terms and conditions.
These are the rules of the contract. You need to know what these terms and conditions are before entering a contract because once you enter a contract you accept the terms and conditions. The two main reasons why a contract may be cancelled are the trader has given the consumer incorrect information about an essential part of the contract an important term or condition of the contract has been broken. Examples of Terms and Conditions A delivery agreement. The trader agrees to deliver the goods you have bought, undamaged , to your home .