This Person Should Have Read The Product And Description Before Leaving A Negative Review
The Japanese writing system is designed to be read from right to left and then from top to bottom. Manga readers are aware that what they are reading will be “backward,” meaning that the cover that appears to be the front of the book is actually the rear. To be fair, the majority of them are aware of that.
Before writing a negative review, this customer should have had sufficient knowledge of the product(s) they were purchasing and reading. If they had done some investigation instead of just assuming they were correct, then they would have understood that it was not an error that occurred during the printing process.