Sent a Samsung Gear S3 watch because the battery q...

Sent a Samsung Gear S3 watch because the battery quickly discharged, then waited 10 days for the watch to come back, replacing a defective component, but unfortunately my back button no longer worked. Why is a function test of the watch not carried out first before it starts the customer is returned?
Had to send it in for the second time, which I find very annoying and also costs 10 Fr postage each time.