Vw Service

On 23 November i took my Polo Vivo car for 120 000 service at Vw Klerksdorp,when i left my car i indicated my air-corn is not blowing cold air if they could check it for me.The following day which was Saturday, i went back but i was told workshop doesn't open,cos i realize my air-corn is not working and its even making grooming sound,so went back on a Friday.I asked the manager why my air-con is not checked or any feedback on the problem,he said they could check for me but i need to pay around 900 for diagnosis because i was not charged for aircon and clearly vw did not check.my argument is i brought in my car i specifically indicated the air-con problem and the lady wrote it down and vw themselves didn't even picked it up during servicing the car, but my argument is i paid 6400 for service,so why would i wanna pay again while it have been included in the services.i am not happy with the service ,that's clearly show vw incompetence i would not service there anymore after 6 years of using your branch.and my manual was damaged by water no one explained how my service book fell into water and it was not even stamped and filled in. You guys don't satisfy customer but put money first.