Gmail - Dispute transaction

I am having SBI credit card for more than * years. On * April **, * unauthorised transactions of ***** each were done on my card at Flipkart. I filed complaint regarding dispute transactions. While doing transaction using SBI credit card, OTP is delivered on both SMS and email. Someone hacked into my Gmail account and used the OTP received on email. After doing total transaction of ***** he deleted all the mails having OTP and transactions details.
On the other side SBI is saying that these transactions were done by using OTP. OTP were successfully delivered at your registered mobile number and registered email ID, after this it is not our responsibility. So SBI closed the disput transaction complaint in the banks favour. Now SBI is asking me to clear the payment dues. After charging penalties and interest the amount of ***** is now became ******.
Now coming to hacking in my Gmail account, I had set my mobile phone as login method in Gmail. It means login is not possible without using my phone. But login was done without using my phone. He deleted all the mails of otp from trace folder also. I didn't even receive any notification regarding login from some other device.
Now who is responsible for this huge loss?
I think Google is totally responsible for my loss.
It is more than two months now. I can't sleep in the night, I can't eat properly, every time I think about this only. I am in depression. Please help me.