Is it permissible for a competitor to manufacture spare parts of the same quality and packaging at a lower price than their original supplier, without the supplier's knowledge? Is this considered deception of customers? And is it permissible for us to adopt this approach?

It is forbidden to sell counterfeit parts and attribute them to the original supplier or give them the original brand name, as this involves lying, deception, and fraud. The Messenger of Allah (peace be upon him) said: "Whoever deceives is not of me," and "Cunning and deceit are in the Hellfire."

However, if the parts do not bear the same brand name and the seller does not attribute them to the original supplier, then there is no harm in selling them.