Ebay question?

Well recently I have been using ebay alot, and past couple of days been trying to get a hold of an amazon fire phone, and I came across a cheap 64gb for £300, and I won the bid

I paid up, then the seller started telling me that he couldn't touch the money as the details were wrong on that paypal account.

He then asked me to text him to get the right email address, obviously I grew way to suspicious and told him I was uncomfortable with this and requested a full refund.

He has relisted it and I bought it again, and once again he tried the same old chest nut.

I'm now waiting on £700 in refunds, which paypal have confirmed he has done so.

What I want to know is, why is he doing this?

Is he ripping ebay out of some sort of money to gain for himself?

Cause from what I recall it costs to list an item, and he would be losing out on money/