[2019] Why does epic games not want to help?

I’ve been a customer for years now and I got 3 minty codes from gamestop. All 3 of my codes didn’t work so I contacted epic, thinking that they would actually help. I gave them necessary proof that the codes were mine and I said that I could provide more. Their reply to me was “Upon checking, I am able to see that the codes has already been redeemed. I would like to inform you that once it was redeemed the it can't be used any further as it can only be used once.” Yes I know this. That’s why I’m emailing because my codes don’t work. It seems that epic just doesn’t want to help me, even though I am giving them money.