Having issues removing old tile
Since you were not able to do it by hand rent a power chipper, these are electric and have a blade that vibrates back and forth and this makes fast work of tile. I also have used an air chizzle with a wide blade. The problem may also be your technique I have not had two much trouble popping tile off with a flat chizzle, the trick is to hit them from the side at the base, many times they will break loose with 1 good smack. If you are striking down on the tile I have seen tile hold up to a hammer dropped from 8' that was well set to a concrete floor so a change in how you are trying to chip them up may save a rental fee.