Unable to get a refund or replacement for my iPhone's broken case bought from the Apple Store

Hi all

Id be grateful for some advice. I bought an iPhone case two months ago from the Apple Store near my home and have been using it for a month and it has cracked. I took the case back to Apple but they refused to exchange or refund as they said it was not a manufacturing fault as it was fine when it left the store!? But surely if it only lasts a month it must be faulty. I’ve been only using it for its purpose as a iPhone case so I don’t understand. I rang Apple and they told me to send an email. Two weeks later nothing. I tried the chat function to raise a complaint but they said they couldn’t do anything and they told me to call the number again. I’m really annoyed as the case is expensive (UK £49) and isn’t fit for purpose. Can anyone advise what I can do to resolve this and at least get a replacement if I can’t get a refund?

many thanks

[Re-Titled by Moderator]

Original Title: Broken iPhone case from Apple Store