Need to delete my email as it’s been havidd

Hi, bear with me as I’m in my 60’s. My not email has been hacked and I want to permanently delete this. I mmust have had it over 29 years now. I can’t open the emails anymore as someone has changed the password. I have had my booking.com and Spotify passwords changed already and bought someone a digital gift card. I really don’t know what to do now!  Any help would be really appreciated