No non-exchange notices in store

I bought a swimsuit top from your Centurion branch I normally wear size 12 but this particular top was a bit too tight. When I wanted to exchange it for a bigger size I was told that swimwear is not exchangeable and that the cashier should have told me that. Now, who should suffer the financial loss if no one told me anything? Me? Nowhere at the swimwear section is there a notice that swimwear is not exchangeable, nothing is mentioned at the cashier section (not verbally and not on a written notice) and nothing at the back of the payment slip either. And perhaps I should mention again that it was a top, not the bottom part of the swimsuit.