I'm getting ghost images on multi prints to the point it is unreadable, is this the drum or fuser?

The only way to tell is to start a print and power off when print is still inside. If you see the ghost before the fuser it's the drum, if clean before the fuser, it's the fuser. You can also open the back door and look at the fuser roller with a light, the fuser roller should be clean but if the roller has images it's time for a fuser.

I suspect you have people taking the blank pages that print out after a fax and feeding them back through the printer to save paper. The old paper picks up a charge when fed through the first time, pulls toner up the second like a magnet, and deposits the toner onto the toner drum. When the next sheet comes through, the image pulled from the last sheet (or the sheet before) and is transferred over the new image. Change your toner and print several pages to the printer, see if the image fades and goes away. If it does, tell people to either stop feeding the blank pages through, or to at least turn them over and put them at the bottom of the paper stack. This will give it time to dissipate the charge before feeding back through.