Given reviews from Amazon, classify those review based on their content into two classes: Negative or Positive.

Let me give you an example: I've read this book with much expectation, it was very boring all through out the book
The answer to this example can be: Negative
Here is why: Review writer does not like the book because it was boring, therefore it is a negative review.

OK. solve this:
My order was for a complete set which was supposed to be 11 volumes but the package came with only 9 volumes. I contacted the seller he replied that he has mentioned in his post that it had only 9 volumes which does not make sense. If he was offering 9 volumes only he should not have this under " Complete Set". plus the order came 10 days after my order placement. Not happy with the sellers service at all.
Answer:
Negative