Good Mobile Service Centers in kochi

hey fellow cocos i currently reside at kochi. im using a redmi phone and i think its battery backup has been reduced by time. when i quired in redmi service center they told me a X amount and thrise the price id it is a board isuue. im not confident about how these people handle the product and i must say the price was wayyy expensive than what i thought it could be. so can u guys help me out here.