Processes in Microsoft 365 for setting up Office apps, redeeming product keys, and activating licenses.
Since this was purchased through Amazon, a third-party retailer, that transaction is managed by Amazon, not Microsoft. Microsoft's support page confirms this: they can't reissue codes, cancel, or manage billing for subscriptions bought through third-party retailers, only the retailer can.
You'll need to contact Amazon customer service directly, they can resend the activation code or confirm your order details.