I would be grateful if anyone can tell me how to get a compensation for the items stolen from the luggage in my case: I have been flying SFO-FRA-MSQ two days ago with Lufthansa (actually the first flight is operated by United Airlines, but this is what Lufthansa sold me in the first place). My luggage was lost and found today. I've received it from a courier, but maybe 1/3 of all items were stolen (it weights 5 less kg now!). BTW I didn't sign that "lost luggage" paper and didn't hand it back to courier. How should I approach LH to get a compensation? All stolen items were bought from Amazon during my stay in US and I have invoices for them all (about 500$ total).

Sorry if this have been explained before, I appreciate any advise!