Currently there is no crypto police that will catch those hackers and scammers so there is a very little chance that we can ask for some justice right now to those victims.
Hackers and scammers are evolving every now and then so for those exchanges and investors they should do their best to strengthen their security everyday if possible so those hackers will have a very less chance to bypass their security. That is the best thing that they can do right now as we cannot depend to any police as of the moment.