Tvs Motor Company — is labour charge included in coupon service (free service)

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New Delhi, Delhi, 110044

I have a apache 200 rtr and during my second free servicing i was charged for changing rear brake pads as labour charge... I asked the mechanic about it's cost and he told me it's fir 450, but when i went with him to purchase the brake pads it's for around 318 rupees, i told him mrp is rs 318 how m a supposed to pay rs 450 for this. Then he said 100 rupees for labour charge. How can i be charged labour charge when my first 5 services are free