Disgusting service

I had my Alfa serviced at Penta Menlyn in January this year. Part of the service entailed, replacing the airfilter, which I provided. On the job card it mentioned that they replaced it. 5,000 kilometers later my vehicle went in for another non related service at Glenridge motors. They thought they would do me a favour and check the airfilter and other regular maintenance points. I was shocked to learn that my filter was never replaced and in a very bad condition. I took a photo as proof and still driving around with this filter as proof of a job not done at Penta. I contacted Penta Menlyn numerous times, was told by a lady called Rene, every time that the matter was referred to her manager and he would contact me. This does not happen. Out of desperation I tried to contact the dealer principal Gideon, also a unsuccessful quest. I find their attetude disgusting and their service integrity, wanting.