VOUCHER NR NOT WORKING !!!!

Its the worst service I've ever experienced. I received a voucher claiming if you spend R600 you receive R200 off for purchases online or instore. the voucher was vailid until 31/05/2021 . I've tried to do a purchase online on 31/05/2021 whereby the voucher nr was not accepted on the system. I phoned the customer care whereby I stated my problem, send a screenshot of the voucher to the required email address and was informed the query was send to their IT division however I will still receive within the next few minutes a new voucher in order to do my purchase online. I waited another 30minutes without receiving the new voucher . I phoned again was on the line with a customer care agent almost 20minutes whereby I ended the call. The ref nr for the Case is CS-328732