OP, I am sorry you are disappointed. If your trip is still two weeks away, have you considered changing resorts? I'm not saying it will be easy, but it should still be possible, unless you are staying DVC on points. There have only been a couple times in all the trips I've made over the years where I got hit with a similar issue (only no internet back then, so I got hit at check in) and although I still had a good vacation, it did make a difference.
For those of you who say CR is an "easy" walk, that depends entirely on the person. For an elderly person, or someone with medical conditions (or both) it's not so simple. I know when my Mom was going through cancer treatments we would sometimes do a weekend at Disney just to get away from the routine, and things that many visitors take for granted when it comes to stamina and distance became so difficult at times. So I can understand the OP's concerns, and if I were in their place, I would be looking at alternatives if possible (if not changing resorts, then perhaps renting an ECV for the duration of the trip, if that is within your budget). Of course, for someone with issues walking, that ramp up to the MK monorail station can be a big challenge as well (ever try to push a wheelchair up that thing? UGH!)
That being said, I don't believe Disney owes anyone any compensation if they are providing adequate but alternate transportation. If the transportation change doesn't work for you, then you need to make other plans. Disney has to do what is best for the majority of guests, and sometimes we just don't fit in with what's best for the majority. I would hope that they would be providing bus service to MK and not just assuming everyone had the ability to walk back and forth.
OP, I hope things work out so you have a great trip.