Refunds for Android apps are available by following the instructions here:
If your request falls outside the 2 hour limit, you should contact Google directly.
Developers do not know your details so supplying your Google account details does not help.
Refunds for Windows applications are not available. Sales are final because there is a 14 day trial period which you can use to decide if the product meets your needs. After a license is issued, there is no way to cancel it.
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