Honor 9XC Voucher

I brought an Honor 9XC at Telkom on the 26th of March. There was a promo that I also had to receive a voucher with the device. I have been going from post to pillar to enquire about the voucher and the response is always the same, we will look into it and send you an sms. I eventually did received an sms but it does not allow me to finish registration so that I can redeem my online voucher. I went back into the store on several occasions only to be told today that they can't assist me and I must escalate directly to the person that was assisting me (which has moved to a different store). I need this voucher issue to be resolved. They must honor their promise and give me my voucher that I was promised when I bought the phone in March.