How to fix a grinder that is backing up and mushing the meat
You may have accidentally rounded the corners off on the square portion of the auger and the cutting blade is not seating all the way down where it should be. This is not a manufacture defect rather an assembly issue when you put the grinder together. This can happen when you go to put the plate and ring nut on and don’t happen to see that the blade has fallen forward off the square shaft. Then when you turn the grinder on, the corners of the shaft get rounded causing the blade to not seat correctly the next time you use it. It also doesn’t grind the meat causing it to backup inside the feed housing or the grinder simply jams.
The auger can be repaired simply by using a metal file or grinding wheel to square the four sides back up by removing the burrs that have been created on the upper edges (they will be shiny and sharp), if the auger is too severely damaged the auger will need to be replaced. Once you have the burrs filed down the cutting blade will slide all the way down onto the square shaft of the auger.
Some simple assembly instructions will help you from doing this in the future - The best way to assemble the grinder is with the feed assemble off the main body of the grinder. Tilt the feed housing up so you are looking down inside of it. Place the auger down inside and then the cutting blade down onto the square portion of the shaft of the auger, the flat surface of the blade should be facing you. Then install the plate you wish to use being sure to align the pin with the notch in the plate and the finally screw on the ring nut.