How do I cancel an Amazon Gift Card purchase?

You will need to contact Amazon and CANCEL this gift card purchase. Inform them the code has not been redeemed and that you'd like to cancel this order. You can also manually cancel by accessing your order page and cancelling the gift card order - Amazon Sign-In

Amazon Support US Phone Number
206-922-0880 or 1-888-280-4331

Amazon Support Login To Account / View Customer Support
https://www.amazon.com/hz/contact-us/csp?ref_=hp_new_cu_culink&from=gp