If you can recall the counter person's name, I suggest contacting the store manager to inform them that this person is unfamiliar with the deli stock and rude. Even though it is several days later, this person probably behaves in this same manner all the time.
As for a script, I think you did quite well specifically pointing out the labels of the items you were interested in. I understand your desire to be non-aggressive, but sometimes people just need a bit of prodding to be reminded they are being a donkey.