Not able to use Markham voucher

Five years ago I received a Markham voucher for my 50th birthday from my cousin. Two months later, the whole country went into lockdown due to the pandemic which lasted for months. During this time I misplaced the voucher and never used it. Late last year I found it again and in January 2025 I approached Markham with a request that I be allowed to still use it after explaining my situation and that I did not want my cousin to have wasted his hard-earned R500. TFG then promised to consider it as the voucher actually expired 3 years after purchase but they have a discretion to still allow me to use it. I gave them all the details including the slip showing the official Markham voucher, where it was purchased, date, etc. Just as I was getting my hopes high, I was informed that I must also send the receipt which my cousin would have received when he purchased the voucher for them to check if the voucher was not used yet. This despite me sending them a copy of the voucher which they can surely check on their system and see that it was not used yet. I informed TFG that my cousin had no reason to keep the receipt for 5 years after giving me the voucher and cannot find it now. I think TFG/Markham is just looking for a reason to not honour the voucher. For a billion rand company to do this leaves a very sour taste in one's mouth and my family will be closing all accounts with any store in their group. Oh ... and you know what you can do with that R500!