Travel voucher promotion UNABLE to deliver

I have now sent multiple emails to employee B...... who still has not gotten back to me with an update. I am waiting to receive my R4000.00 voucher as promised if buying a Samsung S8/ S8+ or Note8 on contract with MTN. I have been struggling to get my voucher. They are quick to take your money but terrible at delivering money back to their consumers. Total ********!