Hello,
Sorry to hear you are having issues. Not sure how Stardock software work when purchase via Ashampoo. But, I believe it should be the same as purchased directly from Stardock. If so, you should have account connected to that purchase and you could use this guide to deactivate old activation to create activation slot for new activation.
https://forums.stardock.com/486311/accounts-and-activation-support-faq#reviewactivations
Use the link above to review your current activation and deactivate old activation.
I believe, you need to make sure your Stardock account is linked correctly to the email registered when you purchased Fences from Ashampoo.
Please report back here if you still have the same issue.
Thank you.
Basj,
Stardock Community Assistant.