Setting up new iphone, its icloud locked?

I've just purchased a iphone 4s off of ebay. Went to set it up and its locked to the last users icloud. I have asked for his id and password and am waiting for that back
When i get this i can then get into the phone, how do i then dissociate his cloud account from one i'm going to set up.
I'm asking so i can be quick when i get the info from him.

Just to complicate things further i'm setting up this phone and i havnt got a credit card, i have seen how to set that up with guides on the internet, but just thought id mention it incase its relevant in your answer somehow.

You have to jailbreak it.

You go into setting-icloud and tap on delete account. It may give you another option and in that case select 'keep'. Then simply either restore the phone using itunes on setting-general-reset-erase all content and settings.

If they do not respond you will have to go to an Apple store as only they can remove that lock without a password. Also print out documentation of the sale as they will require that you show you purchased it. Otherwise Apple will assume you stole it and while they will not contact police they will refuse to help you.