He is telling you that he bought it from someone else. He just offers you a "honest" offer. If you don't want to accept it just wait until response from admins.\
It's takes time for them to answer and it isn't gone out of normal time borders..
I see but i think he just want my money.
In my opinion, whether he is honest or not, do not pay any bitcoins. First of all, it is his mistake to trust the seller that it's not a hacked account which, most of the time, it is. Second, it is your account and never have been theirs neither you sold it nor gave them permission to access it (I assume).
Again, all you have to do is to wait for the admin's response.