City Assure Circuit City Protection Plan is a waste of money because they make up exclusions as they go along , Internet

We purchased a Garmin GPS at Circuit City  and also purchased the Advantage Protection Plan.  Recently the power cable that plugs into the car fell apart. The plan is still in effect. As there are no Circuit City stores any longer, we called City Assure (the third party insurer) to determine how to get the cord replaced.  After well over an hour of being continuously put on hold while they bounced us around from person to person, they told us that the cord is a "consumable" and therefore excluded from coverage.  When I insisted they read the exclusion language, it refers to toner, batteries, lamps, and such items as consumables. I explained a cord is not a thing that is expected to be used up, therefore it's not a consumable. They then changed their stance (after an hour of insisting it's a consumable) and said it's an accessory and accessories aren't covered. But no where in the Terms and Conditions does it state that an accessory is not covered. Also, I pointed out that when we purchased the Garmin, it came in box with its essential parts, including the power cord; we didn't buy a separate "accessory" but we did buy a protection plan. They then said we'd need to go to arbitration if we wanted to pursue the matter.  It's a $30 part, so unless there's a possible class action out there, it's not worth any more time than we've already wasted on it. But it smacks of fraud. Circuit City has forever lost our business over this, and before we buy any other extended warranty or protection plan we'll be sure that it's not this third party insurer.