Totoodo.com — Technician damaged my IPhone while servicing

I gave my iPhone for servicing in Electronic City Totoodo service center for replacing the battery. While opening the phone he damaged it and now touchid is not working. After his suggestion we tried resetting the phone and it when to a stage where it is asking to press home button to reset. As home button is not working our phone has become useless.

When we asked him he says he didn’t do anything wrong and says phone was not in working condition before. We asked him to check cctv footage to check whether we unlocked the phone using touchid or not before handing over it to him, but he denies showing us cctv footage. Very unethical and unprofessional service