navtraffic problem in 2007 Prius

I need help, please! My 2007 Prius with navigation has an after market VAIS XM radio installed. I get XM, no problem. When I try to purchase the XM navtraffic, XM keeps sending the signal but it never works. I get two lines on the freeway ... for east and west, for example ... when I used to only have one line for that freeway. So far so good. But there are no colors indicating traffic flow. Is it possible my 2007 Prius cannot accept this? I don't understand it. My husband's 2010 Prius has a whole NavTraffic section of the manual. He gets icons to show congestion aside from cool colors giving info.

Any help understanding why I cannot get this would be appreciated. XM is happy to sell it to me but has no idea why the signal doesn't give me the service.