He said me I have all wallet.dats from 8.5 btc to 10000 btc.Some of them unlocked,i.e he have passphrase for them,some locked,he dont have passphrase.
I'm sorry for your loss, but really? Why would anyone sell a wallet.dat file containing 8 or more bitcoin for only $55? If he truly had the files, and the means to retrieve the bitcoin within, why wouldn't he just access the files and take the bitcoin for himself?
I'm not trying to excuse the scammer, but if it wasn't for greedy people, who abandon critical thinking he would have no victims. Please be more careful next time.