How do I cancel/refund my iCloud extra storage?

The guy I called from apple today was clueless and told me he didn't know how to do it, and then told me the wrong thing!!!

I bought the storage under the impression that it was a useful product, but it wasn't doing what I thought it was supposed to do! I just want to get rid of this extra storage!! I mean, this is ridiculous if the apple employees aren't trained in this! HELP!