I kena once at Proton, not as high cost as your then I cannot bear already, the next service I straight complaint about the charges and they aware at it and do it economically for me. The first charges they charge me at RM158, the second one ~ just RM88 ~ lol ~ I just tell them

"I think the last service charge is too much, and I feels that a lot of thing you guys give me is useless and extra, can you please state me nice price with the thing that just particular necessary for my car, and let me see the item listing before you proceed"

Then they just diam diam do for me, their face gesture did change but I dont even CARE~

The way you reply them gonna be serious and straight to the point, you should google and survey on how perodua service schedule normally operate and see the latest price schedule for each kilometre range service. So that when you get charge at the amount that sound ridiculous, you got your point to tell them and told them what you expect and willing to pay.

Normally if you shut up or ask WHY during the service inquiry, they will just bull shit you on how important the thing needed for your car. But when you realize its actually wasted, your money already go inside their pocket. Next time be alert. Its not that their service expensive, is the person who greedy and aim for commission to make it expensive.