Sold my phone on Gumtree.

I sold my iPhone on Gumtree with a description explaining everything about the phone, that it was locked to EE, that it was boxed and in good condition. The buyer came round to inspect the phone, says everything was fine with it and paid for it. Now, 2 weeks later he has come back to my front door explaining that he cannot have it unlocked because it's a contract phone, however, i stated that i got it from an EE contract when he was at my front door. It's a £400 refund he's looking for and i just don't have the money to pay him straight back after feeling that he was fine with the phone as it's taken him 2 weeks to come back, also i stated everything about the phone that he agreed with. can anybody help?

If you did quote the specs as you say you did, then you've done nothing wrong, and he can't request/demand anything at all. Deal's over.

He also asked me for the Serial number and IMEI of the phone before arriving, am i wrong in thinking that this would be used to check with the provider or a company if the phone is locked or not anyway? i mean, i did everything he asked of me as far as giving him all the information. I'm just worried as i'm pregnant and i don't want the hassle of him keep coming to my door or him asking for police visits to my door.