"Also, what is the proper spelling and origin for the maze ball? Is it Maize?"
Not slick enough, it seems, bro. This is very simple. The maze ball is hitting you in the back of the head because you are just moving from the hips up and returning your head to the strike zone. You have to step off line for it to swing back over your shoulder. Otherwise you’re just training to be a whack-a-mole in an imaginary box.
Push the ball and then practice side-stepping, slipping, pivoting and keep jabbing it lightly with your fingers to keep it moving.
You can make a maze ball out of a sock stuffed with five to ten dollars worth of pennies. Tie the cotton stock tight and drop it into a long sock and hang that from a beam in the basement. If someone breaks into your house you can always use it as a flail.
The maze ball may have originated as a sack full of maize kernels, which it was sometimes filled with. The most common maze ball was an old worn out speed bag stuffed with rags or even an old split sparring glove. In most catalogues it is now called a slip bag as in the listing below. As to whether or not it was named for the maze of legend or the maize it was filled with is now a moot point.