DSTV REWARDS INVALID VOUCHERS

i have won a voucher from dstv rewards, the voucher is for uber eats and is R50 x 2. when i entered the voucher it said invalid,i then complained to their customer care informing them that the voucher will expire end of April, they kept on saying the issue is resolved i must enter the voucher again, until when i enter the voucher it says expired, they have requested screen shots and i religiously sent them many times with failure, its close to 2 months now with no assistance.