What's wrong with my toy helicopter?

I just bought two Propel RC Gyropter from Brookestone. One of them works fine and the other worked for a few hours and now isn't flying properly. When I try to fly it it spins in circles or goes straight back or forth. I tried using the trim buttons but I might be using them wrong. Other than that I don't know what to do.

you're supposed to push the trim buttons in the opposite way it's spinning. if it's spinning to the right hit the left button till it straightens out