I'm not sure why you think Disney has to let you into a park you don't have access to simply because you chose to buy an ILL in that park. It makes no sense. People could park hop free every day of their trip just by buying an ILL in another park.
Disney expects people to know that they need to have access to a park before making plans in that park. They will let you book a dining reservation for 10 people and charge you a $100 no-show fee if you don't have access to the park.
I agree with
@nickys. Guests will make mistakes, but Disney does not handle them by automatically changing park reservations or giving them access to parks they haven't paid to get into. I'm sure you could go to guest services, explain the mistake, and they would give you a refund.