I'm about to have a throwdown with Sears!!!!

We bought a range yesterday, I was pretty stoked to find out they were having a 20% off sale on Kenmore brand appliances.  I just went to their website so I could post a picture here, and I find that tonight from 6-9PM they are having AN ADDITIONAL 10% OFF THE EXACT SAME FREAKING STOVE WE JUST BOUGHT!  You bet your sweet Aunt Betsy I'm going to be there at 6:01PM to ask for an additional 10% off.  I'm so irritated, that's $100 that we could really use for the multitude of other things we need to buy.  When we were there yesterday I saw the signs advertising a VIP After Hours sale (open to the public) but didn't realize it was an additional 10% off the very appliance we purchased.  It would've been swell if the salesman had mentioned that little tidbit.  If they won't refund us the 10% I'm going to cancel the order and head over to Lowe's.  I'd be happy with a gift card for the difference, but cash would be great too.