sounds like it was dropped? if it's aluminium alloy, not sure they would want it back 
I assume you are repeating the theory regarding Aluminium gear, and micro-fractures caused by impact.
Various sources across the internet show there is little appreciable weakening post-drop, and I have not yet found a source with evidence showing appreciable weakening.
Furthermore, if it was the case that a simple drop could compromise a carabiner, surely this would be well publicised by Petzl, Black Diamond et al, as they would surely see rocketing sales as every caver and climber rushed to replace their accidentally dropped 'biners....
For your reading, the first result from a web-search:
https://fatcanyoners.org/2012/05/05/dropped-carabiners/A.
