Break lease, repay rent discount?

Rent it Right

Q: I rented an apartment that was advertised at $1,500 per month "plus discount." My yearlong lease gave me a monthly discount of $100, so my real rent was $1,400. I had to break the lease after eight months, and now have to repay the discount, $800, for those months. I know, I know — I signed the lease with this provision, but I’m still wondering if there’s any way I can challenge this fee. –Mary S.