I’ve lost my mobile and i want to block him trough avast! , but i don’t know how… 
Is there anyone to help me please ?
Dear Customer!
In order to track your phone you should start by contact the person (friend/family member) who’s phone number is set as “friend” number in Anti-Theft.
If the thief changes the SIM card, our app will send a SMS with the current location of the phone and the new phone number (as sending phone number) to this “friend”.
If the friend hasn’t received a SMS, it’s most likely that the original SIM card is still in place or the phone has been turned off.
To locate the phone, the user should send a SMS to the phone (to his original phone number - or the new number if the “friend” received a new phone number) with this content
2222 locate
replace 2222 with own avast! PIN - it’s 4-6 digits, only numbers.
There are many SMS commands available that might prove helpful. For example:
2222 lock
This will lock your phone
All SMS commands, along with a short description how everything works is explained in our manual available at:
http://files.avast.com/files/documentation/mobile-security-user-guide-en.pdf
it’s short and easy to understand.
Of course you can also use our online interface at my.avast.com to communicate with the anti-theft installation - provided that the app was paired with the online account. The upside of the online portal is, that it’s convenient. The upside of SMS commands is, that they are more reliable and will work even without internet connection (which might be relevant if the thief changes the SIM to a prepaied non-internet SIM card)
Regards,
Werner