Hero Motocorp — facing extra charges while 4th free bike service

Address:

Raj Motors , Vikas Nagar near Nala ,110059 New Delhi, New Delhi, Delhi, 6186

Today's i'm going to raj motors, delhi for my passion xpro bike 4th service.
My bike's head light bulb is fuse off. So that they advised me to change bike bulb. And they told me that i have to pay something 200 ₹ for bulb.
When i was see my bill... I was.. Shocking that, the bulb price is 105₹ and they also add another amount off bulb labour charge which was 70.80₹.
It's not fair...
If they told me that our bulb is only 105 ₹ and labour charge is 70.80₹ then i purchased the bulb from there and put it in my bike in 20-30₹ from out side bike service shops.
I'm totally not satisfied.
They are not taking oil charges while filling oil in engine then how can they charge for bulb labour during free bike service period.
Thanks.