Voucher *** Waste of money

I bought a spar digital voucher for a client as an apology for things going wrong. He never received the sms. I forwarded the invoice to him with the details. He tried to redeem the voucher at the Spar at Knysna was told they do not participate. I checked on the website and referred the client to the Superspar in Mossel Bay and sent him a pin. They also told him that they do not accept vouchers. I sent an email to customer care without any reply. This effort to do good for a client just compounded my embarrassment.