Bad service, not answering emails, refusing to pay back my refund

Worse service ever, phone lines do not work. They do not answer their WhatsApp lines. Every-time i send an email i get a notification that they will get back to me in 24hrs. I booked a flight to Durban on the 06th of March, the airline changed times and i couldn't make those time as i was going for a day, Mango refunded them the money on the 16th of March for that flight but still today i have not received my money back. The last email i received from them they said they were waiting for POP from the airline, i called the airline myself and i forwarded them the POP and now they are mute, like they are just looking at my emails and do not want to refund me my money back. I will never book anything through these people.