I have just purchased an FXD RC helicopter A68690. I ran the rotors for about 30 seconds and the aircraft tipped over onto the grass. When I'd righted it I started it up again but only the upper rotor blades turn. Can someone tell me how to put this right, please. Am so disappointed with it at the moment as it's brand new, just out of the box and I can't fly it. Very, very frustrating. Help, please to firstname.lastname@example.org!