Sorry to hear you are having trouble.
Then I tried the offline activation. It gave me the option to download a file type of req. However, when it was time to upload a file, it was looking for a file type of resp.
The app will create a .req file that you save on your PC. After, you go here:
After clicking the activation type image, you will click the 'choose file' button to upload the req file - it will process it - and provide you with a resp file. You save it locally to your PC and go back to the app to have it process it (navigate to where you saved the file).
Stardock Support Manager