Thank you for your reply behuman.
Well, it was a bad experience but also a learning opportunity for me. I think that people should be warned about experiences like mine to be able to protect themselves.
Sincerely, I am not very interested in exploring the rules and regulations of that *alliance and I appreciate your comment about it. I picked up that route and airlines because the trip was a very long journey and the most convenient for me. In fact, the whole reservation process was made through the UNITED website. I also thought that SWISS Airline was a reliable company.
What I know now is that I will thought many times before flying with SWISS Airline again. I honestly do not like them and I do not trust them either, it seems to me that lying is not a healthy habit for a company. That makes me feel sorry for them because they not only represent a carrier but also a country.
As as said before, SWISS Airline refunded me US$ 200 (money that they originally charged me) and, in addition, they sent me a voucher for the same amount. This happened only when I complained.
Thank you again for your attention.