The difference a typo can make

Need another reason to make sure all communication is crystal clear? Just look at the chaos a typo recently caused this worker and her employer.
Sarah Gaspar, who worked as an event caterer for the University of Notre Dame, thought it was her lucky day when the school gave her a $29,387 tip. Skeptical about her good fortunes, Gaspar claims she called the school’s catering department three times, but no one returned her calls.
Gaspar “thought finally something wonderful had happened,” she told the Associated Press, and spent the money on a new car and bill payments.
Notre Dame didn’t get in touch with her until after the money was spent. As you can probably guess, the huge tip was the result of a typographical error — according to the school, Gaspar should have been paid $29.87.
However, Gaspar won’t budge, and now school is suing to get the money back.
Can you count the number of communication mistakes in this story?