The lenses of my eyeglasses are too far away from my eyes and I'm not seeing clearly.
Because of the sizes of the nosepieces, I am unable to move them without
affecting my vision. They are too big and they will be blocking my sight
line. If I try to adjust them, the lenses will be too far.
What should I do?

You can walk into a near by optical center or take it to the place where you bought the eyeglasses,in most places,they will be happy to assist you free of charge.