We can’t post names of other Fiverr users here so don’t but I have had this exact thing happen to me twice by people ordering writing work. Google small SEO tools plagiarism checker, use it to find out if your buyer has used the work delivered and if so contact CS. If they can’t do anything, send the buyer a cancellation request informing him that since he is not willing to accept your order, you are cancelling it and withdrawing his right to use your work in any capacity. If he doesn’t respond, let the order cancel. Then when it does, contact the website where your writing is being hosted and inform them that you are the materials author, that you have not been paid for it, and that they have no right to use it in any capacity. (Don’t ask for payment as this looks like a scam).
The above won’t help you get paid for the article. However, I understand that people acting as writing and web design companies resell work from Fiverr using this exact, “I need revisions, but won’t tell you what they are” technique. In this case, you will be contacting one of these peoples clients and outing them as a fraud and helping stop it happen to you and others here on Fiverr in the future.
I hope this helps.