Having worked in retail before, I find that knowing how to work the store's PA system is invaluable in these situations. The CSM and Store Manger may ignore their own employees, but it's amazing how quickly they move when a customer announces to the whole store, "Hey can we get some help in Sporting Goods? This poor cashier has called for a manger five times and I have places to go. Could we either get a manager over here or could someone give me the number to your corporate office so I can complain about the slow service in this store?"
Works every time!