Wrong box size

I bought schools stalkings from woolworths Wonderpark, They were marked 13-14 on the box, I then opened them to for my child to wear only then I realised that they are actually a size 5-6 in the box. I asked my son to take them back to Wollies Soshanguve Crossing and I was told that they cannot take them anymore because the box is torn they will not be able to put it back on the floor. My question to them was so were you going to put the wrong box with the wrong size again on the floor. I feel that it's unfair that they make it my problem that they packaging was incorrect.