From the front-end, I had created an new account, then I had activated that account by email as any visitor, NOT as an admin.
Unfortunately, I didn't receive any IP Information about the new account.
Then I uninstalled the plugin successfully.
I am very surprised to hear this. It is a simple plugin, there is not a lot that can go wrong. In order to receive emails your administrator account must be set to receive system emails - did you check this? Also have you checked your spam filter? If you want to contact our support I would be happy to figure out what the problem is.