unable to open

I purchased a subscription of an ase study guide on 3/15/2012 and i am unable to opopen it anymore. it says its reached the maximum number of computers that i can read it on. ive only ever opened it on my home computer!! so thinking there was a glitch, I purchased another one of the same guide, and it says the same thing!!. how do i get my money back for both of these purchases? i feel ripped off big time.