This is a copy of the CUV I received after I booked my ticket:

MINIMUM STAY REQUIRED MAXIMUM STAY ALLOWED The fare: Premium Business: ZEEEVZ0V You have no date restrictions for travel The fare: Premium Business: ZEEEVZ0V Maximum stay at the destination 12 months. TRAVEL RESTRICTIONS The fare: Premium Business: ZEEEVZ0V You have no date restrictions for travel CHANGES Review the main conditions for making changes according to your itinerary. • If you have not yet commenced your trip and want to make any changes, the fares that we will offer you will be those available at the time of changing and your trip must comply with all the conditions of these new fares. • If you already flew one of the legs of the trip and then want to make any changes, we will offer you the fares that were available when you bought your tickets. In this case, the new trip must also comply with all the fare conditions. • If your original fare allows for changes and when changing this fare it is no longer available or doesn't comply with the original regulations, you can obtain a new fare by paying the difference. • The fare: Premium Business: ZEEEVZ0V Changes before flight-departure time are permitted with a penalty fee of EUR 60.00 Changes after flight-departure time are permitted with a penalty fee of EUR 60.00 REFUNDS Review the main conditions for performing refunds according to your itinerary. • Although your trip may not allow a refund you are entitled to request the return of the boarding fees. Please remember that in some countries there is a service charge and that this amount is not refundable.

When I tried to change my ticket, they told me I had to book a higher fare. The CUV states they will offer me the fares available at the time of the change. The Z fare was available at the time of my fare, I checked on LATAM's website before I called.

Again, their position had no justification of any kind. The conditions on the ticket were CRYSTAL CLEAR.