Blue Dart Express — Company lost my phone while delivering to service center

Dear sir/mam, I have a Oneplus 6 phone. And it was not working well. So there is option in oneplus care app to book repair online and it will directly get transfer to banglore. So applied for this. Bluedart is official company who picks the parcel. Then blue dart associate came to my home. They picked up my parcel. But now parcel has not reached to the destination. They have lost somewhere. I have talked to them. They are giving any response. I am totally stuck in between. Please help me out over this issue.