All purchases are managed by the respective app store, and we don’t have access to any purchase details, but if you have subscribed to Chordle and are seeing demo banners in the app like this:

Remember that Windows and Android require separate subscriptions - a purchase on one store won’t unlock the other. If that’s not the issue, follow the section for your platform below.
Windows - Microsoft Store purchases
First, make sure that you are signed into the Microsoft Store with the same account you used to make the purchase. You can double-check that your purchase was from the expected account by visiting your Microsoft Store account page.
If the purchase was successful, try tapping Restore subscription in the dialog that opens when you tap Unlock full version.

If that still doesn’t work, please contact Microsoft support for Store license issues.
Android - Google Play purchases
Make sure you are signed into Google Play with the same Google account you used to make the purchase. You can double-check your purchase in your Google Play order history.
If the purchase was successful, try tapping Restore subscription in the dialog that opens when you tap Unlock full version.
If that still doesn’t work, please see fix problems with subscriptions or contact Google Play support for Play license issues.