I've had more than a few oddballs like that, including one who between ordering
and paying via etransfer for local pickup dropped of the face of the earth. over
2 months later he resurfaced saying he'd move halfway across the country
and forgot. Took him another month to remember to pay me for the shipping.
My suggestion is to just sit on it. If the buyer has paid for the order, your
return in in. Just let is sit and see if they bother to realize they haven't
received anything.