Unredeemed voucher can't be resend

In May 2025 I returned shoes and requested a voucher at Mall@Reds branch. They gave me the voucher (till slip). I asked for a gift card but they indicated that they only have a slip and they'll send an sms as well. Today I wanted to redeem the voucher but couldn't find the sms on my phone. The store told me that there's nothing they can do about it. I called the call center and gave them my cell number and they told me they can see that the voucher is not redeemed but there's nothing they can do if I don't have the slip or sms. This is unfair on they customers. They can't even re-send the voucher to the same cell number.