Thank you for your feedback.
We are somewhat surprised by your assertion that no help was given, because we spent quite some time on technical support on the phone, during which various fault finding options were discussed. We also discussed a possible warranty repair of your device which was declined.
As we tried to explain, we are not able to remotely determine why your vehicle produced unexpected readings without knowing all the local variables. What we can do is make sure that our products work reliably by 100% function testing each device, and offering a 1 year return to base warranty, which on this occasion was declined. That leaves us without any real options to assist you.
As stated on our website and in your manual, the sensor is warranted is limited to dead-on-arrival cases because it is a wear part that is sensitive to contamination. In this case it did appear that exposure to high levels of unburnt fuel may have been a factor.