It's not too late to go back in and tell them to try again with a new pair of sights and, this time, do it right. While you're saying that don't be angry or rude, but be firm; don't give them any reason to write you off as a jerk. If they tell you to go fish, request to speak to the manager. If he tells you to go fish, request to speak to the owner. Or, if this is like a major chain store, go home and Google the e-mail address of the company's CEO, then send him a polite and clear explanation of the situation; make no demands, just tell him you thought he might want to know how his troops are alienating customers. Don't ramble, and use correct punctuation and a spellchecker. Include your address and phone number in your signature.
I do this all the time. CEOs read their e-mail just like everbody else, and they
hate hearing stories like this. Nine times out of ten you'll get a call from the CEO's secretary, apologizing and offering to make everything right.
How to find the CEO's email address? First find out his name (check the company web site, and/or Google "Company-X CEO"). Then Google "@companyx.com" (or whatever the company's domain name is); you'll turn up dozens of employees' email addresses. None of them will be the CEO's, but at least you'll learn what pattern the company uses for usernames, like maybe
firstname.lastname@companyx.com. Your email will bounce if you didn't get it right, in which case try the other obvious alternatives, like
firstinitial_lastname@companyx.com.
Squeaky wheel still gets the grease, so start squeakin', man...