Yeah, I did have the problem with staff not knowing what I was talking about. Once I had the brand name, though, they could look it up on their system.
I guess they're not very popular items, because I usually find them either on the floor under the shelves, or on the highest shelf (which I can't reach).
One time they had some amazing rubbermaid cubes. They were cheaper than the regular ones, and had some sort of spray on coating which doesn't come off no matter how much the pigs chew on it. The regular IBEX cubes have a plastic coating that my pigs chew off very easily. They only seemed to stock those for a couple of months, though.