Unreliable

I'm writing on behalf of my sister.She entered Kellogg's competition in January now on 10th March She received text from *** /info.kellogg's @secretary.net requesting her to buy MTN Voucher of R60 so that they can register her reference number into their system bcz she won R250 000 cash prize.After sending they requested her banking details and sent her sms saying they have transfered the prize into her Absa account.Today she told them that the money has not reflected into her bank account when can she expect the money?They asked her to pay R1500 for bank charges fee in order to receive.She must send through cashsend ,pep,Shoprite and Spar.We have checked the number on Truecaller it is registered as Kellogg's South Africa.How can Kellogg's share our information with the ********?How they knew I've entered Kellogg's competition.