why is Jane Eyre treated so unfairly?

Jane Eyre is treated poorly because of her position in the
family.  She is an unwelcome child that her aunt feels bound to care for.  Her aunt is
blind to the faults of her own children and often blames Jane for their misbehavior. 
When her aunt finally gives her over the care of the teachers at Lowood, she sends her
off with a final, spiteful act.  Jane's aunt tells the headmaster that Jane lies.  Of
course, this sets Jane up for a difficult transition into her new school.  Jane is
treated with indifference and cruelty by many people in her life because of her position
as a poor, orphaned girl.  She has no money and no one to look after her.  She is an
outcast and looked down on by many in society.  Eventually, Jane's aunt returns to the
plot with more cruel news.  She has kept the letter from Jane's relative a secret
because she did not wish to see Jane prosper while her own children were not.  Much of
Jane's unfair treatment stems from her position in society and her aunt's
spite.