Use it ALL or lose it Nandos voucher on Multiply shop

I am a regular buyer of vouchers from the Multiply shop and its been such a great invention up until my recent purchase. I bought a R500 nandos vouchers and upon presenting it to the teller at nandos and asking how it works, i was told they don't issue change or gift card but the balance will remain on the same voucher number after my purchase. Later this week i went back to use up the balance and was told the voucher number has zero amount.

I am disappointed by such 2 well established brands unashamedly running a **************** and **** on their loyal clients. Why would i pay R500 only to get 200 worth of food. I want the balance of my voucher multiply. This is insanely disappointing and hurting that no education is happening with your partners on how to handle vouchers bought on your website.

Your terms and condition on the Nandos voucher are ridiculous as you dont have the same T&Cs on other vouchers. Please fix it and stop running a ****