I was trying to make point that even though a piece of jewellery does not have CoA or invoice it does not mean it is not authentic or super suspicious. In fact, replicas often come with so called "full set" with the CoA included.
I have been dealing with pre-loved VCA for quite some time now and there are many of them which do not have any documentation because in fact a lot of people do not keep it. Many get them as gifts, many just don't bother because they are not into that kind of thing, many people just do not know this jewellery "authentication" world so deeply. You would be surprised.
Typically with replicas you can see their tiny flaws upon close examination or even in the photos.
Going back to the original point of the author: have a very close look at the earrings, engraving etc. Everything has to be perfect, find photos of similar authentic items and compare very closely. If you have pics to share - post them here, I will have a look.
What I like here is authentic used pouch haha, and the "balls" on the earrings - high chance it's authentic but of course I won't tell 100% from 1 photo.