That sure does stink. You may want to speak to the manager about it.
A saw like this with a saw guide is quite easy to use to cut your panels down to size. Since you can set the cutting depth to be just below the thickness of a single sheet of hardboard, you can cut the panel on the floor or on a folding table in the garage, holding it up off the table/ floor with cheap 1x2 or 2x2 furring strips. No need for saw horses or a table saw. Lay the panel on several 1x2 strips that are running parallel to the cut and make sure the blade doesn't touch your support surface.
https://www.rockwelltools.com/versac...w-rk3440k.html
https://www.homedepot.com/p/Empire-9...E902/203175575
You will need to transport the full sized panels which is going to require a truck. Maybe a friend can help if you don't own one.