Goldsmith cheating in grammage

I have been buying gold ornaments for years from a particular goldsmith (sonara) in Dar who has always been giving me great discounts. Three months ago, I went and bought two sets of earrings. After I left the sonara, I was unsure of the grammage of the earrings and I went back to get each of the earrings labelled with their actual weight. Fortunately or unfortunately I went into the neighbouring sonara shop believing it to be the one I had just come out of. Luckily the person there was very cooperative and agreed to measure the earrings for me. To my dismay the grammage was much less than what the seller’s scale showed me, meaning that his scale is deliberately calibrated to show more grammage and cheat customers. I think I have been cheated by this sonara for the past ten years. Is there no law that regulates the weighing scales that such sonaras use?
OP, DarThere is a specific Act- the Weights and Measures Act that protects you. Infact such scales are to be regularly inspected and you have all the rights to report this to the Weights and Measures Agency (WMA) who will take appropriate action. The WMA can both fine and imprison such a sonara.
You also have the right to report this to the police for investigation as this is a cause of concern for all purchasers of gold from such sonaras. Such behavior amounts to a criminal offence which is imprisonable.