Can You Check The Back?
There is nothing worse than when you go specifically to a store to get something and they are sold out of it. We have all been there and it really does suck. We have all heard of the secret of there always being more stock out the back, which means that we have all probably asked once or twice before.
More often than not there is nothing out the back that should be out on the floor. So instead of questioning the authority of the employees, perhaps your time would be better spent at a different store searching for the thing you need than complaining about the one you are currently in.