if you have a paypal account and the seller does, if they are happy to do so, you can give them your email address linked to your account and they can send a refund that way, plus any postage costs if they want the item back. if your both in agreement, they could also do a bank transfer, you only need to give them your name, a/c number and sort code. The seller could easily do one of these and shows the sellers true intentions, because they could be saying they are happy to refund, knowing full well they are past the 30 days for you to do anything anyway, but failing these, your best bet is a chargeback, as suggested by @tressygirl