Poor service from Bidvest McCarthy VW Menlyn

I paid for a front nozzle last year (3 December 2018) when I brought my car for service and your office said they didn’t have in store. I didn’t get any call of availability of stock. I brought the same car yesterday (3 May 2019) for service and requested that the part be fixed and I was told by Brandon that your division wanted proof of payment. I must confess that I’m actually appalled by that question and the kind of service I received from your division. It’s more than 6 months now and in spite of having paid in advance you still request proof of payment even though, you are able to pick up from your system that the said part was paid for vehicle HR 64 BV GP. I sent the managers in charge email on 3 May 2019 but as of 18 May 2019 not even a reply has been sent