Hi there Janet,
I'm Andrew, a community manager here at Trulia Voices, and so can speak on Trulia's behalf.
To fix an error on your Trulia estimate, click the "Too high? Too low" text next to the value of your Trulia Estimate. Then you will be given the opportunity to update or fix any of the details on your home, resulting in a new valuation value.
Should you feel that the new valuation is still not accurate, you can also tell us us how much your home should be worth and why and we will take that into account when looking into your home.
Is there anything else I can help you with?