It is disappointing but at the end of the day people are people and sometimes have to take time off work - it's how the world works. Fortunately, you were able to be offered a full refund and could have gone to the TKTS booth to catch something else. There is no "bait and switch" here, in my opinion.
That said, this doesn't mean I feel some criticism is deserved to theatre practices though. When there are "below the title" stars out that are clearly a draw to the show, refunds should be given. In London, where the star is currently out of "Funny Girl", refunds should be given. But in this specific case, I think you have been accommodated for well.
Give me claws and a hunch, just away from this bunch.