Dishonest guttering business

we mistakenly paid an invoice twice. Despite numerous phone calls and e-mail messages, we are unable to get our refund. Telephonically , Theuns Fourie promised to refund us the overpayment, but has not done so. He now does not answer our calls or respond to e-mails. We have visited his premises on 3 occasions to collect louvres which he had to spray paint - still do not have our property.