IF she was really rude without help from you (were you being unpleasant too, be honest...) and IF you are sure she was not just having a one-off bad day and IF you really feel so passionately that you MUST do this thing to spread more negativity in the world, then go ahead and call and complain. But I offer you one piece of advice: complaining is an art. If you want the person to listen truly to you, speak calmly, articulately, describe the situation and what was wrong or bad about it. THEN offer what could have been good about it, what you were expecting. COMPLIMENT the store at the same time, e.g. "This is my regular store, as you can imagine, I love the furnishings there (or whatever) and the staff are generally so friendly, so you can imagine my shock to be treated by this service person in this manner on this occassion."
Ideally, what you should have done is address the salesperson in the moment. Ask them are they okay, they seem a bit upset... Salespeople are not robots - they are human beings too. You could turn around their whole day by showing a little kindness and sympathy, and thus creating a positive experience for the other customers to be served by them after you. Think of the good you could have done if you only thought about it with love, instead of anger or fear. Shame on you. Now you must learn from this.