3 for 2 means poor QUALITY

So I went shopping for undies last Sunday at Woolies Hemingways. They always have the 3 for 2 special with ladies underwear ( and I have become a woolies fan for quality oer the years ) but i was so disappointed when iI wore one of the undies it literally came aprt at the seams ( and yes the underwear was my size) . I just didnt know that because the underwear was offered at a discounted pricce woud mean I dont get the trusted Woolies' QUALITY.