Lenovo — Service complaint in warranty

Address:	Surat, Gujarat, 395017
Website:	www.motorola.in/home

I had bought a moto g4 plus phone on 26 July 2016 and till current date I had never gone for any repair or service. About 2 months ago my phone's power button stopped working then I went to Service Center RAN Service, Office No. 2, Ramsha Tower, Above Vijay Dairy, Adajan Circle, Adajan Patiya, Surat, Gujarat 395005 for my phone service. They told me that power button has to be changed and it is chargeable because it not covers warranty but they don't have that button with them so they asked me to write down my no. and article I needed for, in a register. I did the same. But till date I had never got any phone call from them. After that now I can see a spot in screen of my phone since 25 days, so I went back to same service center. This time they told me that its not cover any warranty, and said this is physical damage. I contacted Customer Care by mail and after a long discussion and after sending pic of my phone, they told me today to go to service center and to submit phone their so they can issue a job sheet and I have to send that job sheet to customer care. The person in service center looked my phone and said that it is physical damage. I asked them, can they prove it ? They said that no prove but we can't do service in warranty term.
Not the problem is that,
1. My phone's power button was missing.
2. In right bottom of my phone their is an scratch (they used this word).
3. A scratch with volume button.

Not the clarification for the same are as below :
1. Service Center did't provide me new power button and my old power button was getting disturb using back cover to phone. So I separated it with T-PIN. and I have that button with me.
2. The word they used scratch was just color discard due to rub with Hard Back cover.
3. Scratch with volume button was due to use of T-Pin for separation of power button.

The most important thing is that Power button problem in moto g4 plus is not only with me it is with 40-50% persons.

I asked customer care to send me a mail saying "THE PHONE HAVE PHYSICAL DAMAGE AND WE CAN'T COVER IT IN WARRANTY". they said they can't do. After a long fight they said we can't sure but we try if there any provision to use these words we will send you the mail.

Kindly help me to fight with them.