Just shoot MonsterMike a PM and let him know the details. I am sure that he can help with your situation. There is a sticky thread in here as well that you can post up on so he gets the message quickly. No biggie.
The purpose of the slipper is to have a component that will absorb shock from the drivetrain without destroying your diffs or other driveline components. It is meant to do this by having some level of slipage setup. If you do not have enough slipage than something else will absorb the impact. It seems to me that your spur gear was that component. Like I stated before just shoot MonsterMike a PM and see what kind of response you get from him. He backs his parts as long as you do not use them in an incorrect manner.