What's a corporation commission officer? If the jobber can be convicted in court of a crime, you may get restitution. You may have to check with your insurance company and/or an attorney to see what damages you can recover.
This all assumes some damage was done by the lower octane. If you heard no knocking and noticed no power reduction, your three engines may be ok. You could have a mechanic pull all the spark plugs and look for signs of spark knock. I think that can reveal itself with tiny metal droplets on the plugs.
[This message has been edited by Robert W. Roe (edited 01-04-2000).]