****mers alert

Good day, today i got a phn call from a guy named Johan Coetzee claiming to be a financial manager at vodacom from Johannesburg, Midrand.... Apparently I've won a voucher or rewards of R5000. My name was drawn on Monday but i received the call today, i went to the nearest vodacom store and did enquiry on Johan they told me it's a ****. I called the number back and no one answered. I just want all the vodacom customers to know