I have won a vouche...

I have won a voucher from betexchage and I redeem at my Shoprite voucher account it gave me 16 digits for MMA pay my way voucher now I can't use that voucher and om not getting help from Shoprite it's being 4 days I've being calling them and they calling me back to follow up my complain I lost 3000 and airtime I'm not getting help