Need help to unlock my phone

Hi,
Few weeks back i have installed Avast Anti theft for my Samsung S Duos, I installed after i lost my nokia lumia 630 :frowning: two days before i interchanged sim card in with out remembering about the Avast! its samsung dual sim card mobile, unfortunately its giving a message like Lost or stolen wit siren tone & asking for Avast PIN… i gave my sister number as secondary number two times she received sms about PIN number. But she couldnt give it that time to me… Now PIN number is not getting receive to her number even after several trials… How to resolve it… My mobile is blank out completely its asking for PIN number how can solve it… Please help…

Thanks & Regards,
Rajkumar G

http://www.avast.com/faq.php?article=AVKB135#artTitle (Changing a SIM card)