Mi not accepting/denying service under extended warranty

Few months ago my wife purchased an MI phone online from their official site. At the time of purchase, I also bought accidental coverage at an additional cost. For this I have the original invoice that I received by email and order ID. 3 months ago my wife got the phone damaged in an accident. Since then am trying to claim the warranty. But this is what is happening : 1. As per MI, accidental damage services are outsourced to OneAssist. I called the oneassist helpline only to be informed that they have no data on me. They directed me to call to MI India. 2. I called MI India. They said as am under MI protect my query has to be to oneassist and said that they can't help. I and my wife kept calling both the no.s just to be referred to the other. Finally getting really frustrated I went to an MI store. From there they said they can't help and gave me a service center land line no. I called them and it again did not help. 3. Though oneassist did not help me, now they started calling me to sell oneassist plans. I started getting multiple marketing calls to add to my frustration. 4. After getting no help via customer care no.s I went to a MI service center on a working day. There was long wait and I had to wait almost half day to get my turn. I was after 34 others. When my turn came, they were quick to tell me they can't help me as am in mi protect. I very informed them am not going to go unless they give me a solution. I also said that for me MI is Mi. I don't need to know to whom they have outsourced what. I needed the service promised to me. Finally they asked me to call MI call center from there. It was only after the mi service center person spoke to to the call center I got my first complaint no. I was promised a resolution on 48 hours. 5. After two or three days I again called MI as there was no resolution or call back. In between, I also send them a very detailed email for which I got no response. In this call they apologized and promised me resolution in 24 hours. He also mentioned that they will initiate action internally for the mistake that happened from their side. Again there was nothing in 24 hours. I send another email, saying I will post the issue publicly in social media. After a while I got a call from someone at Oneassist asking me to email my invoice to their email id. I was told I will get a call in a while to fix all problems. I did that and then again nothing. Like this almost two weeks passed. I called oneassist twice. Each time I was asked to wait 48 hours. I also tried to contact one assist via their app. I was asked to wait 48 hours there too. 6. The most difficult part of oneassist is that they won't give us a complaint no. No matter how much you insist they tell you it's not needed. But each time you call, they have no clue about previous call either. You simply have to explain it all in full detail each time. Char limit reached. More to the issue. What can I do?