PayPal issues. Solved now. You just need to wait.
Purchases via PayPal have been working poorly for the last day or so.
The technical reason is that the PayPal IPN servlet on minecraft.net got bogged down because paypal.com was really slow with replies and the IPN server was single threaded, so paypal started resending ipn causing even more bogging down. I fixed the problem by removing the “only one purchase at a time” limitation, and IPN verifications are rolling in again.
According to Paypal, there’s still about a hundred or so purchases to resend, so if you bought the game recently but didn’t receive it, just wait for a while while paypal retries. It’ll get to your purchase sooner or later.
And I really, REALLY need to set up a better support system for when the game is in beta. You deserve better than me getting flooded and not replying to emails.