Specifics on car size are misleading

We booked a car that said it held 7 passengers. We made the decision so that the 5 of us would be more comfortable and have room for luggage. What a shock to find the seats that were considered seats 6 and 7 were not real seats - I'm not sure a two year old child could have sat in those seats. And, had we actually need the seats there would have been NO ROOM for a single bag. The advertising of a 7 passenger mini van is VERY misleading. I urge caution when booking - do not take the specs at face value.