Zillow Api Mortgage Calculator Broken?

I've been working with Zillow's Mortgage API - specifically GetMonthlyPayments, and it appears to have just gone down, along with all associated documentation and URLs (http://www.

Solution 1:

I have a contact at Zillow and asked them what happened to their mortgage calculator.

Response: "They killed it. I don't know why." And an apology about there being no communications around this.