Sorry to hear about the activation issue, to fix this pls. follow the steps as mentioned below carefully:
Here are detailed activation troubleshooting instructions for you :
2). Right-click and select "View page Info" as shown below:
3). Goto "Permissions" tab , uncheck "Default" and click "Allow".
4). Click the ACTIVATION LINK provided in the "Thank-You" email and try a video download in mp3/1080p format.
THE DONATE BUTTON WILL BE VISIBLE IN PRO VERSION AS WELL BUT PRO DOWNLOADS SHOULD WORK.
NOTE : If you still get the donation prompt, make sure no third-party addon is blocking cookie access. Recently, an update to addon Ghostery caused issues with activation. You should try disabling all addons and see if it fixes the issue, after checking you should enable the addons one by one to find the culprit. You should then proceed with whitelisting videodroid.org and Youtube.com domain in that addon.