Starbucks Mud Pie ice cream bar - where?

I have a Starbucks Duetto Visa card. This is really stupid, but I got it because when you get one they put $25 in Starbucks money on it. Plus, as you buy things, you build up some money on the Duetto side (cash) that you can use in a Starbucks store.

When I get my monthly bill I get some kind of coupon. I have one that is good until September 30 for Starbucks mud pie ice cream bars. A free box!!

The thing is, where can I buy them? My coupon has been in my purse for quite awhile–it is getting very crumpled. And I can’t find these ice cream bars anywhere.

I guess I’m going to have to call my grocery store and beg them to stock an item then give it to me for free.