did you check spam folder?

I know that some receipts for games I redeemed went to spam, while normal receipts were delivered to me at the same time.

I know for sure that mine didn't go to spam, they were definitely missing.

Yes, but I don't see any blocked email.
I'll write again to support, but I'd like to hear about other similar situations.

As you pointed at my post already: No nothing in spam. Something seems to be broken.

Lately, I've also not received receipts for games redeemed from codes, but have for purchases.

I've redeemed several gift codes lately (thank you!) and I haven't seen an email receipt since the cows - oh wait, the cows are back. Hold on. No, they haven't seen any receipts either.

No receipts for games I redeemed by codes.

I have never gotten a receipt for games redeemed by codes. I assume the person who bought the gift got the receipt.