Voucher received wasn't working

I'm very disappointed with Sportscene, on the 15th Dec 2021,i reveiced a voucher of R100, 00 with Ref no ML5ETD87I18QFSH which expires on 31/12/2021, 2hrs ago(today) I was @Sportscene-Empangeni,bought some stuff only to b told that this voucher does not exist, the cashier tried several times in capturing this number but dololo, he even called the other guys to assist, my question is WHY DO U SEND THESE VOUCHERS WHEN U KNOW VERY WELL THEY DNT EXIST, we as clients wait in these long Q's only to b told its not working, what kind of service is that? Or y'll a trapping us with your lousy marketing techniques, pls sort this it's so unprofessional from the business point of view,I must mention though that the guys @Empangeni branch were very helpful in assisting me.... Pls do betta Sportscene.. disappointed customer, pls call me on email