The Mac my Apple ID was signed in with via my iPhone is not my Mac.

This has been going on forever: MY Apple accounts bs my son’s Apple accounts are hacked and have been or 2.5 years. I have a least six different Apple accounts the hacker uses to charge different Apple products to me so I pay for them and Appl can’t give me info. On what the charges are even for. Now, I was just told my phone was linked to a “Mac”. No other info. I know hacker uses a Mac, as do I. What’s going on?

[Re-Titled by Moderator]