In that case 'I'm sorry for your loss and thanks for the deflation of bitcoins'.
The importance of the private key is the first thing we need to understand.
That is an important issue i think, i think that it is th most important thing to keep our wallet key very safe. Because once we lose our bitcoin wallet key, then it is difficult to recover and more chances are that we will lose our bitcoin forever. To me i have already lost my two wallets security key, but the amount of bitcoin in these wallets were not so much.