seemed like a scam, but who knows...
Not a scam, he is/was trying to sell his bitcoinmax account to me.
payb.tc requires proof of ownership of the current withdrawal address before he'll change it to the purchaser's address.
bogidu's current withdrawal address is one that he can't send from (it's an exchange account deposit address) so payb.tc suggested an alternative method the owner demonstrating a deposit to the withdrawal address of the full account value (basically amounts to an internal coin transfer for the owner)