If you would like to cancel your second line, you would need to contact customer service. I understand you are currently abroad and might not be able to call from your location. Alternatively, you might consider sending @FidoSolutions a PM. Once they verify some information, they'll also be able to access your account. In addition, they can also be contacted via Live Chat, Facebook, or Twitter. Those methods can be accessed via the contact page posted above.
Hope this helps 😀