Sonsio, Inc Big O Mechanical Warranty, Warrany on work is not worth the paper it is written on Arvada, Colorado

on Jun 8, 2011 I paid $261.18 to have the a/c on my '93 chevy Suburban fixed.  It came with a 12 mo/12,0000 mile warranty. On June 4, 2012, I called a Big O in Colorado Springs, CO to have them look at the a/c because it was blowing hot.  I was within the mileage/time frame for the warranty. They told me they will not honor the warranty because they "think" there is a leak & it will cost me over $700 to find out if there is a leak & if it leaks they still will not honor the warranty!! This warranty is provided by Sonsio out of Arvada, CO.