The voucher apparently expires so we had to use it or lose it.
Also, the voucher was only good for the ticketed passengers it affected, so we could not use it for one of our daughters, for example.
Also, when we did try to use it we were told it was not valid for many of the seats/tickets we were trying to book. Where it was valid: upgraded (business class or first class) flights, flights with several layovers....
Such bullshit.
In my experience (at 800k lifetime miles at this point), the squeaky wheel gets the grease. If you're not happy with something, call to complain.
Vowing to never use their business again (so my loss is limited to a one-time event) and recommending everyone to do the same has worked out pretty well for me --- I can make peace with the experience and we slowly weed out these bad apples from the world
They have already determined that they don't care if you fly with them or not, so why not make sure they don't get paid for experience? It is only fair.
Hell, do a credit card chargeback.