Stolen phone with avastAT

I gave my phone to my sisters doughter. She lost it one week ago and i knew about it today:/ A ihad avast anti thieft in that phone, but a can’t contact with it. I can’t remembar in what gmmail account a had in that phone. In my account in my second phone, i don’t have this lost one in devices. What should i do?

http://www.avast.com/faq.php?article=AVKB116