losses with a very large value ,usually what I hear is that a hacker uses a file type of virus that can send data on the target computer to the hacker's computer ,but for such problems there is usually an anti virus that detects it, does the OP turn off the anti virus performance? Why are important files not saved properly
of course, fantastic values can be retrieved very easily, is there any mistake from the op himself being able to experience this and whether or not a reliable save is made. this is a question for many people if one gets hacked and its worth a lot.
it could be that what you said happened because the hacker had sent a type of virus that he didn't realize was actually opened and hacked the data on his computer, but if he used the original anti-virus, there would obviously be a warning. did he ignore it, or could there be a trick of his own by not realizing that he was giving access to his computer, because the hacker's unconscious request was thought to be wanting to help.
but from this there is a lesson in not being able to trust anyone and keeping valuable data as safe as possible with reliable security.