Bad service from Pay just now and a vendor associated to them

My wife bought a handbag at Dirty Leather, a vendor on the pay just now platform. After a month, the handbag was not delivered. We requested a refund from Dirty Leather and they informed that they gave pay just now instructions to refund the purchase cost which is fully paid. ....No refund received and no response from pay just now, telephonically, on the app and on watsapp.