Very disappointed that coke give me a prize I can't get

I been winning the xmas and coke campaign that airtime and data and I am on contract and it won't give me my prize and on top of that there no terms and conditions to explain what the prize is or how to switch the prize to something I can use as my phone contract is unlimited calling and data and I have no response from CCBSA or coke south Africa even after emails and text messages where they said I won a prize and there no terms and conditions to explain what to do or email about my issue