Asus India — mobile phone battery

Resp. Sir,
I have purchare asus zenphone 5 mobile. Now after three years i have to replace mobile battery. So i went to asus service center in ahmednagar. They told that battery prise is rs.600 + 500 sevice charges. I was shocked that for only changing battery they take sevice charges of rs.500. So i called costomer care officer for conforming the charges. They told the charges was correct. They told we have company policy.
So this is totaly wrong to take so much sevice charges.