Answer:
I contain six letters, minus one and you got twelve. What am I?
What goes up but never comes down?
I am often sold by children entrepreneurs in summer time
I am round. I have only one line. Circle is not my name indeed. What am I?
Iron roof, glass walls, I burn and burn but never fall. What am I?
Whoever made me don't want me. Whoever bought me don't need me. Whoever use me don't know me.