The fact is, doing any kind of hardware production in China, you have to be aware Chineese have different value system and you would not be suited doing any business if you throw tantrum at any sign of apparent dishonesty (assuming the company was involved which they could not have been as they have been the ones damaged the most).
If the company does screw you (like replacing components for something cheaper) they typically will not be thinking they are doing anything wrong. They are just testing if you notice and if you do not they will say it makes no difference for you but saves them costs.
The way to work is then verify everything and politely point it out. If you notice they will correct apparent mistake.