taptic Engine Feedback damaged by Authorized Service center

i had recently given my iphone for service on 14th jan 2018 for Authorized service center for battery replacement issue and they had asked me 1,180rs for diagnose and i payed them but they said the battery is fine.. but the battery had been malfunctioning after reset also of charging jumps from 30% to sudden 80% very rarely i had told them to replace battery and now they replaced the battery after multiple follow up by me and requested them daily in there service center to generate the billing payment and they generated after 2 days as my request and now they have replaced the battery but the taptic feedback is not working (no vibration at all they damaged it during replacement and they are telling me to bare the loss of the hardware cost. is this even valid reason to tell by authorized service center for there damage caused. when i ask the diagnose report they are not giving it and they are acknowledging it as there was no error when i submitted the device. now how to solve this issue with apple as its there fault of damage done to my phone