I lost 81% of my crypto assets with the Celsius bankruptcy. I did receive 19% back. I have not sold the crypto assets. How do I claim the capital loss for the 81%

I lost 81% of my crypto assets with the Celsius bankruptcy. I did receive 19% back. I have not sold the crypto assets. How do I claim the capital loss for the 81% of crypto assets that I did not get back from the bankruptcy filing?