It is just part of the culture, even though Americans and Europeans despise it.

Chileans lie about everything.  I have heard people promise to come to dinner and not show up or even intend to do so (even after making a commitment). I have heard a girl speaking to her mother and lie to her all day whenever her mother called, telling her mother that she was in town looking for a job when in reality she was out with a new boyfriend and other friends. I have seen many students cheat on tests and brag about it. Chilean students have an amazing number of sophisticated cheating devices. I have seen secretaries lie about their bosses not being in the office. I have seen parents lie about their children’s actions or grades. I have seen people lie when giving directions because they would rather lie than look ignorant about not knowing where some place is.
Chileans lie to get ahead, they lie to get away with something, and they lie because they do not want to hurt someone’s feelings or make someone worry if they were to know the truth. Moreover, they tend to think that Americans and Europeans who do not lie are somewhat stupid.
But before you jump all over Chileans about their sins, think about what sins dominate in the USA. Is Chile that much worse? They are accustomed to lying. Americans are accustomed to other sins: abortion, homosexuality, greed, gossip, perjury in family court, etc. And the sins we are accustomed to do not seem so bad or shocking to us. Alternatively, Chileans are shocked by American sins.
Nevertheless, dealing with people who frequently lie is a challenge. Being accused of likewise being a liar is even harder for us to deal with.
Chileans do, at least, honor written contracts almost without exception. So if you have a contract you have certainty in Chile. Contracts are thus used for everything from phone service, to employment, and to home rentals. Otherwise, you can not take a Chilean for his word necessarily, unless of course you are paying him for a service (like a taxi ride or fixing a car you are buying from a used car salesman) wherein he has a vested interest.
Of course, Chileans do not always lie. They probably tell the truth most of the time. But they lie so much that one cannot reasonably expect to trust what they have to say. Among your friends, especially in Evangelical circles, and (perhaps) your family members, you have a far lower percentage of lies being told, but it still happens.
When you run across that rare Chilean who does not lie, often an Evangelical or a traditional Catholic, make him your friend forever. It is good to have such people around when you need someone you can count on. In Chile, a person or “man of his word” (un hombre de la palabra) is literally worth his weight in gold–if you can find him.