Rotten fish before expiry date

<p>I bought a tray of prawns due to expire on the 27th of july...upon getting home i opened the tray and was hit by a smell. Not a fishy smell but the smell of rotting meat. Clearly the prawns must have sat way beyond their consumable period and this is a serious food poisoning hazzard. Not to mention the fact that they were quite pricey! I demand a refund for my purchase!!!</p>