How can I recover files from Bitlocker encytped HyperV virtual disk?

I have a virtual disk that I created with HyperV. I encrypted this disk with Bitlocker and put my files in it. I deleted all these files by doing Shift+Delete with a momentary anger and turned off the computer. I turned the computer back on, removed the bitlocker password of the disk and tried to recover the files by trying various recovery programs. The files arrived, but they are corrupt and cannot be opened. I didn’t write anything to the disc, it just sits. How can I recover these files?