After negotiating (and agreeing to) a price with the OP, the subject of escrow came up. The OP said that he does not like using escrow, so I tell him that if he wishes to not use escrow, he will need to send first (and suggest that we use 'tranches' when he sends credentials to a few accounts then I send payment, and repeat until finished). He then declines to sell his accounts to me as "the price is not good for him"
I highly suspect that the accounts do not actually exist and that he is trying to scam. I would suggest proceeding with extreme caution
EDIT: the OP has agreed to escrow and escrow has been funded. The OP has claimed to have provided the escrow with the credentials to the 10 accounts. I will update when the trade is complete.
EDIT2: The trade was successful.