Oboist has all her equipment lost by bad airline

From Emily Ross:

I have this horrible situation with Brussels Airlines and could use some advice. They lost my suitcase three months ago which had, amongst other things, all my reed-making equipment and cane in. The total value lost is over 2,500€. After months of phone calls, emails and waiting, they’ve now come back to me saying that due to me not being able to provide receipts, they’re going to give me 600€ as a gesture of goodwill.

Obviously this doesn’t even cover half of what was lost which also included many clothes, concert dresses + shoes and toiletries/makeup etc. I simply do not have the funds to replace all of this and need a better solution from them. I’ve called and emailed to complain and say how unacceptable this is. I don’t know what my rights are when it comes to these things, and I fear I’m about to be massively fucked over by a greedy company, whose fault it is in the first place!

Any help/advice would be massively appreciated!