Zillow isn't indicative of the actual home value. It's just what the zillow algorithm is spitting out. In many instances, this is number is wrong. The median error of zestimates is nearly 8%. Also to add, your agent should have gone over how this works. I'm surprised they are no longer in contact with you. I typically text/email my old clients monthly to see how everything is going and wish them well. Ultimately, don't sweat the zestimate. It's a worthless number.