I think the store will be very understanding that you thought you were getting the exact fabrics on the pattern and I think they will let you return it.
I also think that when kits are made, they decide to change it up a bit every once in a while and that's not really a wrong thing to do. If every single kit bought was the exact same thing, then lots of people would have the exact same quilt and that would get boring.
Let the LQS know that this is the first time you have bought a kit and it's not what you expected. They will probably let you return it, but tell you to know for the future not to always expect the same fabrics as what the pattern shows.
Please let us know how you make out. :thumbup: