Refund missing for two years

On 24 April 2014 we had our Toyota Fortuner serviced after the airbag emergency light was noticed, the invoice was paid and a couple of months later we were informed that this was a factory fault and we would be refunded. We are still waiting for a response. Today, 17 March 2016, we received an sms for additional service and we again followed up on the refund. A lady said she would contact my father about the refund but sent an sms for the service reminder, He is 73 years old and I decided to follow up on his behalf, the person he spoke to this morning is now on leave (without contacting him about the already paid refund) and the lady that assisted me said the refund was paid in August 2014. I then had another check at our most recent service date of 30 September 2015 and recalled that upon our inquiry we were informed that the refund was still outstanding. I was promised today that someone will get back to me with a remittance advice to indicate who received this refund as we had not received the refund. The only problem we have is that since 24 April 2014 NO ONE has ever contacted us in regards to this refund. Can someone please show us to whom the payment was made or pay it.