First and foremost: product key retrieval does not work and has been attempted multiple times. The canned response emails from support@ and sales@ have suggested it plenty already, and it doesn't need to be suggested again, kthx.
A few hours ago I looked into purchasing Start10. I already had a license for Start8 and saw a button to check eligibility for the upgrade rate, which came back successful. So I purchased that while signed into my Stardock account, using a PayPal account that had the same email address (receipts from both Stardock and PayPal came to the same address/inbox, so yes, double-checked).
I received a confirmation email with a download link, but no activation key.
I downloaded and installed Start10 to a freshly formatted (as in, totally wiped, then Windows 10 reinstalled clean -- no remnants of anything) laptop, and no other Stardock applications had ever been installed prior to installing Start10.
I followed Start10's activation pop-up and attempted to activate by signing into my Stardock account, which returned an error that no license was associated with it.
As I said at the top, I emailed sales@stardock.com and got a canned response that led me to check my downloads page for a key (it's not there), use product key retrieval with my order/paypal email (no Start10 key in the response), or come to this forum (hi). The product key retrieval page suggested emailing support@stardock.com as well, which I did, and received the same canned response.
Any helpful help will be greatly appreciated.