Hi Veronica,
So I believe it's nothin to do with Samsung. Android is made by Google and given to carriers (EE, Vodafone, O2) who then play with it, add things to make it their own, test it and when they're happyy with it release it to us to install. As this seems to be affecting people with different carriers (i'm o2, you're EE) this might be an android issue (google not samsung).
In any case... what i did was i was able to get into boot menu and one by one i tried the options to see if i could make it work (my phone is 2.5 years old so out of warranty i assume, plus i'm enough of a hacker to figure it out myself and not give my phone to anyone for a month to fix it). Nothing was working, so i tried the option to factory reset it (knowing i'd lose everything on my phone), i knew that i didn't have much to lose as i've recently backed everything up to my laptop so only had a few bits to lose. This reset still didnt make it work. It only came to life after i plugged it in, went back to boot menu and chose to power it off.
then i started it again with just power button and left it on the White samsung logo on black screen (which was stuck there for ages before, and after about 10 mins i finally saw it was doing something). it still took a long while for it to finally install Oreo and it reinstalled all my apps (i had to remember passwords that i used years ago which was fun) and took hours to redownload everything and its not far off where i had my phone. i only lost a few photos, videos and some music - most of which i can get back. By signing back to samsung and google on the phone, it brought back my texts, contacts, bookmarks etc, but only back to mid March, last time it did some backup (it did it itself).
Question is what have you got on it that you'll lose and what has it automatically backed up without your knowledge to google and samsung (cuz it does backups automatically most likely).
Another question is whether you've done the factory reset in the boot menu as i had done?
From the stage of it not working at all, i doubt there's a way to access it unless you had things backed up on memory card, in which case you just stick it in another phone or computer. but if you had it on the phone memory, you need to patiently play with it until it comes to life. I'm happy to help as much as i know. If mine came to life somehow, good odds yours will too.
SO tell me more about what you've done to it (accessed boot menu?) where is it stuck? Do you know how to make it restart? where does it hang, etc...
Cheers,
Daniel
