Hi all...I just got an OMSTAR 20" folder for a graduation gift and the first time I go to fold it back I can't get it to fold. I released the clamp and tried to fold the hinge on the frame, but it won't budge. Any ideas on what the problem might be? This is my first folding bike and I am kinda learning by doing. The chain is off too, but I think I can get that. Thanks for any help you guys can give!