I would go in and talk to them directly and honestly about it. Just say "I know my crank angle sensor is out, and I have mods, but I really don't think they could have caused the problem." You'd be surprised at how many will listen. Just be prepared to be turned away. If this happens, calmly leave and then contact SOA. In my admittedly non-essential opinion, the SOA rep will probably be willing to listen. If that doesn't work, you will have to go to small claims court and make them prove that your mods cause the failure (which they didn't). Good luck.