Defective clothing in store

Yesterday i went to Ackermans Belhar once i was there i saw 2 reversible sleeveless Puffer jackets one for my son and another one for my daughter Style number where 118749 for my daughter unfortunately i cannot find the sleeveless puffer jacket on your website for my son. Once by the till i noticed both jackets had thread coming loose from where the zip went up and down. My daughter's jacket had thread loose by the sides of the jacket. I went to look for other jackets and to my dismay i found exactly the same problem threading coming loose from the other jackets. I queried this by the cashier and was told i had to complain about manufacturing of the clothing to the factory shop. How can a customer complain to the factory shop but you are selling the products in the store.I was very upset with the attitude of the cashier. I had to leave the jackets because i was not happy with the quality and for the price which would have Cost me R320 for a defect. My son and daughter was also very upset when i got to the car and i did not have the jackets with me.My question is how can the store sell defective clothing to customers and when customers complain they are told to complain to the manufacturer. Is it not the stores responsibility to do a quality check before items are put on your shelf's.