So the first question would be one of liability Was the art designed in a way that was correctly manufacturable but was backed up incorrectly? If so did you see a proof and approve it? If it's manufactured differently than you approved or, just have them reprint it…it shouldn't cost you anything. If not, you have a decision to make… you could have a sticker omit that implies it was intentional to get the attention of your target market I’m guessing that we’re talking about a vertical trifold and not horizontal. A horizontal piece would really only have one way to fold, and it would always be head to head, whereas to read correctly sometimes a vertical piece needs panels of opposing orientation. That way when you open it it reads right side up. If you're reviewing an electronic file only, this might not be obvious…so it's always a good idea to print your own comp even with online services if something folds. Best bet is to reach out to the vendor and explain your situation. No printer wants to make their money from your mistakes…you may be able to get it reprinted at cost even if it was your fault. Most shops would be interested in gaining a customer and helping educate you about the process