One size doesn't fit anyone

I purchased 2 different packs of "one size fits all" size 6 -12 adult male socks, but when my 11 year old son who wears a size 7 shoe tried to put them on the socks do t even go over the midpoint of his foot, they are extremely tight cant go over the heel. I cannot understand how it could possibly be size 6 to 12 adult socks.

I can't go back to Canal walk Mr Price for a refund or to exchange as getting there and back would cost me almost double what the socks costs, so what's the point.

The 5 pack blue hounds was R109.99 The 3 pack Fash Teal was R79.99

Transport to get there and back is more, my point is should the company not Confirm correct sizes are sold as per the packaging and labeling.