Poor and arrogant service agent

Friday morning , i booked for inspection service , at Bellville Barons . I was served by Yumna Malan the service agent very unprofessional . She gave me a price of R3600 written with pen .I asked her that last year september, my car was booked for similar service, and i paid R1500 including labour. Why do i have pay triple the price. She couldnt explain that , I asked her if does Vw offer lift ,her answer was " we dont give lift to strangers anymore " . I brushed that off ,and left the dealer . Later that afternoon when was about to fetch my car it was parked outside whereas two cars were parked inside also, which belongs to customers and ready for collection. Mine was parked outside with leaves (plants) in the passanger seat allover the interior. Not washed and polished at all the exterior . Before i made payment the lady gave me an invoice ,which was totally less than the intial price . I asked her what happen to the R3600 . She couldnt explain ,the new price was R2868.50 . Which was still ,expensive considering the price i paid last year of R1500. I asked her again what was changed in my car . She told me it was Oil filter, Airfilter, Pollen filter and ***** and that cost a labour of R1945.50, but spark plugs were not changed . While questioning the lady , Yumna told me that she has already knocked off and left her table . She wont be able to attend to my question and yet she already explained everything , sayijgbthis irritated. I was treated very badly and my car was left dirty ,with all the old parts changed were left in my boot . And when i address that to Yumna she appeared irritated and angry and she told me straight that she knocked off already . I was planning to come back for another service for brake fluid flush , i dont think, i will ever make use of your services ever again or even recommend someone else .it was the first time being treated like that at VW Barons Bellville. My question why i was charged, this amount for oil change? And why prices flatuate, there is no fixed price ? No proper pricelist for services . And Sparkplugs werent changed .