I can not play battlefield3 because not activate although i have account

Hey there, 

Please try the troubleshooting steps below and let us know if that helps:

Delete EA License Files:

• Make sure the EA app is closed.
• Press the Windows key and "R" at the same time.
• Type or copy and paste "%ProgramData%\Electronic Arts\EA Services" (without the quotes) into the new Window > ENTER
• Enable View Hidden Files and Folders
• Delete all files in the "License" folder.

Clear your temp files:

• Press the Windows key and "R" at the same time
• Into the new window, type or copy & paste: "%temp%" (Without the quotes.) > hit "ENTER"
• Your Windows Explorer should have brought you to the "C:\Users\>your user name<\AppData\Local\Temp" folder. > Delete all files and folders in it.
• (If some files or folders can't be deleted, reboot and try again.)

Unfortunately did not work :(

I'm sorry to hear the steps didn't fix that for you. 

Just to confirm, which platform are you using to launch the game?