International courier company lost my package

Requesting help on legal advise and directions from experts.

I had sent a package through an international courier company that promised for guaranteed service of package delivery. The package was sent from Bangalore, India to Canada. The documents inside the package were confidential as it was for immigration purposes including bank account related information. The courier company did not deliver the package on time as promised as well as they have confirmed that they have lost the package. They sent an email saying that they are initiating the claim process. I am not sure what does that mean and how much is the claim going to be. If they are hoping to refund just the courier charges that I had paid them, then I believe that is not sufficient enough to cover the opportunity loss that me and my family is suffering. Due to the courier companies negligence, me my family lost the opportunity to send the document to the immigration office on time. I have spend a lot of time, money and effort to get all the required documents that was asked by the immigration office. Now there is no way that I can send my documents again and I have lost the opportunity as they will not accept documents after the deadline.

My question here what are the next steps I should be taking? I have patiently waited for the company to complete their internal investigation till now and that is done and they have acknowledged the loss of my package.

As it is a international courier company and their Canadian team lost the package. Do i have legal mandate / validity to take any legal action against their India office from where they promised on time delivery? 

What are the extend of damages that I can claim? Any cases from the past that I can refer to ?

Sincererly appreciate any help and guidance.

Thanks much,

Vinod