Skype wifi does not disconnect

I got the following problem twice at Amsterdam airport. After connecting to the wifi I could not disconnect by clicking on the disconnect tag. Go to page saying youre already connect and no way to disconnect even by switching off the wifi or by killing the application. I was twice charged of the full 30 minutes. Be careful with this app ! In my case I wont use it again...

Headphones sxb about Skype WiFi, v1.4.1