Account upgrade with false promise of more money?

Yesterday I got a message (in-program) stating I would get $1,000  back, but if I upgraded for $39 I could itemize and my return would be over $1,400.  The program had already told me I was better off not to itemize, but thinking it had discovered something new I hit OK.  It upgraded me and immediately dropped my expected refund to $929 - I didn't change any information.  Now I can't figure out how to go back to free after this false enticement.  Guidance?