Depends on where you flew from. Ex Europe, I was successful in asserting my Montreal Convention rights (since they use that to limit their liability, surely it establishes their obligations as well). They covered the cost of the things in the bag that I specifically needed during the multiple days that my bag had its separate vacation.
Expect to have to go three rounds. First round, email denial. Second round, token small sum as an exception. No email, just cheque. Do not cash it as the endorsement side of the cheque is a waiver of further liability. Ask for the remainder. Remainder arrives. No email, just cheque. Perhaps they don't want emails that can be posted on social media.