Avast Anti theft stop messaging

Hi all

I have used the app Avast Mobile security. Recently I bought a new phone so I didn’t need my old phone anymore. After doing a factory reset I sold my phone on an ebay kind of marketplace.
The app is still sending out messages though. The problem is that I can’t stop these messages.

I’ve tried to login in on myavast.com but it doesn’t seem to know my email login adress.(tried all email adresses I used in my life) I also tried making a new avast account, but it doesnt allow me to add my old phone so I can stop tracking it.
I’ve searched all forums for answers but without any result.
As I am going abroad soon I need the app to stop sending messages, because this can become very expensive for me.

How can I block the messages which are being send or deactivate the app???

Thanks in advance for any assistance

Your in the wrong area, can you please post in the mobile section http://forum.avast.com/index.php?board=37.0