How to manage refunds on Shopify when dropshipping?

Hi everyone, I have a question regarding the logistics of processing a refund on Shopify. I’m dropshipping through AliExpress.

Let’s say someone buys a product on my store but decides he/she wants a refund.

He emails me asking for a refund.

Do I wait for the AliExpress supplier to receive the product before processing the refund? If I don’t, then anyone can just buy my product, ask for a refund, and not send it back. They get to keep the product and I lose money.

Can you please help?

Thanks

P.S. Sorry if this is a silly question but Shopify’s page on processing refunds didn’t explain this properly.