There have been a few posts on here lately from people who have posted a "negative review" online and then received some kind of threat regarding a claim of "defamation". So let's be clear about what defamation actually is.
Defamation only occurs if "you knowingly make a false statement or make a statement where you are reckless as to the accuracy of that statement." If every word of your review is factually correct, then it is NOT defamation. The threat is a standard response from people who think that making that threat will force you to delete the review. If your review is factually correct, then stand your ground and don't delete it.
With that said however, it is always very important to remember that usually when people write negative reviews, their emotions are elevated and the review often reflects this. It is therefore extremely important that you only state facts, and NEVER let your emotions dictate the wording. If you get emotional, you can easily end up saying something that can get you into a lot of trouble. The trick to writing reviews, is to be factual and generic as far as possible.
My advice to anyone in this situation is to check your review and edit it according to the following:
1. Check the wording of your review, only keep what is "fact" and delete everything that is "opinion". (eg: "we were quoted $40 but were charged $50" is a fact - "the service wasn't worth $50" is opinion.)
2. Delete or replace everything that is based on emotion. (eg: "this place sucks" is emotion - "based on my experience, I would not recommend this place to anyone." is a fact based on your own experience.)
3. Never name individuals. (eg: Never say something like "Mr Smith said..." or "Abby said...". Always use a generic title where you can, such as "the staff member said..." or "the employee said...". If there are issues with multiple employees, use "staff member 1", "staff member 2" or "employee1", "employee2", etc.)
4. Never bring up gender or anything else that may be interpreted as discriminatory. (eg: Never say "the female employee said ...." - just say "the employee said...".)
5. Avoid using job titles wherever possible. (eg: If you have a problem with a staff member and then with a manager, don't refer to the manager directly, use something like "superior", "supervisor" or something similar. Likewise, if your beef is with "bar staff" for example, just use "staff member(s)" or "employee(s)". Don't single anyone out unless there is only a single aspect of multiple services provided that you have a problem with, and you are perfectly fine with everything else - in which case, you probably shouldn't be writing a "negative" review in the first place.)
6. Always name the location as many business are privately operated franchises and your negative experience doesn't necessarily reflect the service standard of the parent "brand name" as a whole. (eg: For something like fast food or accomodation, never use "company name" on it's own - always use "compnay name at suburb and state".)
If you take the above precautions and you still receive a threat regarding "defamation", then either:
1. Don't respond at all, or
2. Respond with "I stand by my review as being factually correct. If you have any issue with that, then I invite you to take any action as you see fit."
From a legal standpoint, no business can succeed in any legal action against an honest review if the facts claimed in the review can be substantiated.
For a plaintiff to win a defamation case, they have to convince a court that "at the time you published the statements, you either knew or were reckless to the fact, that your satements were false or misleading." This is the very essence of defamation and without this, there is no case.