Refund delayed

I bought a car a we buy cars Germiston and it was faulty upon roadworthy test. I returned the car and chose another one for less amount. I was told the refund will be paid within 72hours. I am still waiting. I've called, emailed, sent WhatsApp even through customer care. No help so far. The sales reps are good and helpful, but those dealing with concerns, queries and finance are not.