I have been shopping for a road bike, and tried a Trek 58cm. I could barely reach the pedals with the seat at the lowest possible setting and the reach was too long. What surprised me was that the Trek site indicated that I needed a size 58 after inputting my height, inseam, and whatever else their system uses. Ended up with a 56cm. I'm 6'.

Some shops offer a 30 day return policy. Might see if there is something like that if you bought it from a store. Otherwise, it's time to sell.