stock in the back room to see if you have the part, and if you don't, how hard is it to warn the customer ahead of time "we have to order the part, so we can't do the work until <fill in the blank>"? It sounds like it's not a part necessary to safely driving the car, so it would've been courteous of the dealership to maybe have someone drive the car out to you. Did anyone offer you a loaner?
I'm sorry you're stuck at home dealing with this. Maybe you should sic your kitties on them. A treat-deprived cat is a mean cat <g>.