Faulty Bra Sizes

The bras at Woolworths doesn't match the size on the bra or the tag, I have measured the bra with a measuring tape and the 32B that is supposed to be from 70cm till 84cm doesn't even reach 70cm so I went to exchange it, I took a bigger size and the B cup on the 36B isn't even a B cup it's the size of a D cup. I just feel like this could cause severe problems especially with youths since they are very self conscious about weight.