Can anyone make a suggestion to protect my computer from a persistent hacker? I do have a good anti virus and malware services and my Mac firewall is on

There is this lunatic coming into my computer (I had an email account used in a social network and it seems that the programmer and CEO of this network is a lunatic hacking patrons' computers. Yes I close the account, but I still experience someone taking over my mouse, removing before my eyes, a document htat I am working on in Word and moving it to the trash and I just heard that noise and can't open because it is in the trash, try to open the trash and I can't...have to call Apple tech support... What a nightmare..I heard that a physical firewall can be helpful, but I have no idea how to install it. Any and every opinion is appreciated (perhaps I should change my IP number not with a VPN though bc my research ch tells me that they cause more problems than they solve, most just pumping adds to your computer without protecting it in any way