Returned goods never arrived, but customer still gets refund !?!?

Customer wanted to return his items (approx. £ 250 value) as purchased by mistake.

Amazon authorised the return and give customer an Evri returns label. Evri collect.

After 10 days, nothing from Evri. Customer wants his refund, involves Amazon, and of course gets a full refund. It's not the customer's fault and it's not my fault.

3-4 weeks have passed now and nobody takes any responsibility.

The blame lies with Amazon and Evri: I cannot contact Evri as it's an Amazon return because I'm not the sender or the account-holder. Amazon don't care to help, they just gave customer a full refund and wash their hands of my financial losses.

So end result: I lose, everyone else wins.

Maybe it's best to stop selling on this platform. The only winner is everyone else except for the sellers.

I wish I could close my Amazon account and be independent.