Why the same casino shows different codes
It's common to search one casino and find three or four different no deposit codes. That's not necessarily a sign that any of them is fake. Casinos run several offers at once: a public one on their own site, partner codes for individual review sites, seasonal codes for holidays, and app-only spins. Each partner promotes the code it was given, so the web ends up with a patchwork.
Ozwin shows how wide that spread can be. Its official site lists OZWELCOME-A for an A$10 chip at 60x. Other Ozwin codes have been published with chips from A$10 to A$50 and their own caps. Ripper is similar: we list TOOEASY for 20 spins from the brand's own rules, while other codes for 10, 20 or 70 spins have also been printed. When codes conflict, we keep the one closest to the casino itself and note the alternatives in the review where they matter.
The practical lesson: if a code fails, it may simply belong to a different partner or have expired. Ask support what's current rather than trying codes one after another, which can look like abuse on the casino's side.