They won't let me change or return the ticket

Before buying a ticket we must ensure the conditions offered by the fare we want to purchase, once the conditions may vary in case we need to change the date, the ownership of the ticket or the refund in case of cancellation. We must make sure if it allows us to make changes or returns. 
 
In the event that our fare allows us to exchange or refund and the company does not meet the conditions of the contracted tariff, we can resort to the Courts of Justice, since it is a private matter concerning the conditions of a transport contract that is the legal way to assert our rights.