I know jewelry.
Maternal grandparents were old money. Received lots of jewelry as gifts over the years. Can spot fakes a mile away. Fake stones, gold overlays just by the color, etc.
If the one place you went to was no good, try another. Like any other industry, you have a few bad apples - don't let it spoil your opinion of the entire bunch.
Do you know how to tell gold overlay vs solid 14k or 10K?