People using Vodacom to **** others

I was called by a number *** there was a guy who told me that his from Vodacom and saying that I won rewards I was chosen. He then explained how I can go and get the rewards at any vodacom store after getting confirmation messages from. He said I had less vodabucks so I had to buy more airtime to send to him so that I can get more points I send the R110 airtime he asked for.All of sudden he said I didn't participate in any donation so I had to donate R360 for the Nelson Mandela Donation at Pep Store or Ackermans. I told him I didn't have it then he told me to go look for it I then cancelled and asked for my airtime back he said I should wait after 3hours. After the 3 hours I called and it was another consultant saying that I had to wait till tomorrow I should stop calling the because their busy with other people