Lost all ETH after install chrome extension few minute

I have installed the extension from chrome extension store, lost all 1.2 ETH after install extension few minute ,then I transfer another 0.8, after 1 days, it auto transferred to the same address.
I am 100% sure no one have my 12 word passphrase .

my address : 0xfe0c00505d48c7cd92d0886E02EB5bf7E4710955

I have submitted the ticket but no one help, any idea ?