Jet bra sizes not the same even in one pack. It's a ****

Good day, I purchased a pack of bras and matching panties at Jet. When I arrived at home I fitted them. The third bra was way too big than the other 2. The tag with the size was the same with the others. I called the store just to report as there was nothing they could do. Why do we get *******? JBG is a ****. Never will I again trust this retailer. And recently I bought a navy bodycon dress which I wore once and it's got ontshontshi...what quality is that?