On the 30th of April, I purchased a key for the Xbox Game Pass on PC, but I didn’t redeem it straight away since it was a non-stackable code and I had to wait for my subscription to end. Yesterday, I decided to use the code I bought, only to find out that someone in Poland had already redeemed it on the 5th of May.
I contacted support, and after providing proof that I could not have redeemed the code, they gave me a replacement key within 12 hours. Great customer service and a very understanding merchant who resolved the issue quickly.