A major store has failed to live up to the terms of their most recent shopping promotion . What repercussions can I expect if they take offense to my comments. Everything I will say will be true and I have the documents to prove it in a US court. I am conserned because I have been told many times, YOU AREN’T IN KANSAS ANYMORE TOTO, and Taiwanese comsumers don’t have the protections of their EU or US counterparts. 
For defamation etc., see Art. 309 to 314 of the Criminal Code (law.moj.gov.tw). (One “yuan” means NT$3.)
For your specific case, make sure you have an accurate translation of the fine print before you accuse them of failing to live up to the terms. The Legal Aid Foundation (laf.org.tw?) offers brief consultations for free, and if you’re a resident you can also apply to have them take on your case.
I think there’s also a consumer foundation of some kind.
This doesn’t answer your question exactly and certainly isn’t legal advice, but maybe you’ll find it interesting.
My wife got pissed after a conversation with a translation agency a few years back. The guy’s attitude was bad and was answering very strangely to her questions. Got to the point he was accusing her of being a spy for competitors or something. (We had used them several times for past translation cases). So she posted on her Facebook account about the incident and told people to use them at their own risk or something like that. She also emailed him about her feelings about the incident and mentioned she would tell her friends not to go to him.
He went ballistic. Kept calling and calling and emailing and emailing. Threatened to sue if she didn’t take Facebook post down. Some of the things he said were odd to say the least and my wife felt it wasn’t worth he trouble. So she took down the post. It was up less than an hour.
A couple hours later the police called. He was there making a complaint. Apparently they knew him well. Wide explained her side and all was done.
A couple months later we got a letter to appear at our local court…
At his point she researched him and found another girl was going through the very same thing…almost exactly the same. Except she refused to take down her post. In fact, she posted more. The guy even threatened to hurt her in an email in some “valiant” attempt to protect his business. Wrong move of course. She sued him and he was sentenced 1 month in jail. He paid the one month fee to not go. And later he lost his case against her.
Then my wife’s case…it never made it past the preliminary determination whether it should go to trial or not. 10 min in front of the panel and they decided he had no grounds for the lawsuit. I’m sure his past lawsuit(s?) and jail sentence didn’t help.
If you take anything away from this, I would say technically you may be saying/writing 100% correct experiences and legally you may be within your rights (no idea for sure; best find this answer) but that doesn’t mean they can’t make your life full of headaches. Being a major store, they may not even care. But if they do, they certainly have more money in their pockets than that translation guy.
Personally I would do it if I were in your shoes. But that’s just me. I do reckless things at times. So don’t take my advice. 
PS> I should mention…there were a LOT of calls and emails from that guy over those few months…