Im sorry this happened. First of all, you did not deserve to be harassed like that. Secondly, you should have asked them if they had any pee or poop to wipe up, in other words get back to work!
I agree with everyone else. Go back to the store, find the "little punks" and their manager and tell them what happened. I bet if you confront the "little dummies" in front of their manager they will squirm like little babies. Im glad you wrote them too. Going in person will let them know that you are serious. Keep us posted.
By the way, Koda is adorable and looks like a yorkie to me!