Yes you can delete all the accounts you want, tell FB you want them to delete your data, stop using any and all online email (yahoo, google hotmail, outlook etc...) but as most internet savvy gurus will tell you your data will never be gone.
Even FB had admitted in the past that they don't really get rid of data fully, and it can take months if not years.
Google, Yahoo and Microsoft (hotmail, outlook etc...) have all admitted to reading your email regardless, for advert targetting purposes, if you use POP, Imap or the webmail pages. Many companies use these online mail services, like Virginmedia etc... there is NO free email services that don't make you pay somehow.
If you want totally private email get your own domain and run your own mail server, costs a few pound per month and guarantees privacy.
Amazon, Apple, Google, Bixby, and any other assistants or voice controlled devices ALL listen 24/7 and send stuff back to base, Amazon only admitted it because they got caught out.
Even if you don't and have never used the internet your data can still be online, data from shops find's it's way online because quite a lot of shops use online databases to keep records that can be accessed nationally. They very often use cloud services, from the likes of Amazon and Google, to keep data backed up from their servers.
Doctors and the NHS have online databases, police, airports, ferries. Just because you don't have access to them doesn't mean they are not there.
The best thing to do is stop being paranoid and enjoy life.