After enabaling filevault i get apple logo after login and nothing happens! new mac 4 day in and still cant get myself setup!!!! ****** off

I bought new Macbook pro as my 2 year old laptop needs to go in for repare(1st in 15 years of using apple) and i need it for work. Old laptops trackpads gone, and 'y' key dosent work. plus batter lasts 10 min. so its up for some serious repares.

So i bought a new mac, installed nad migrated my user data using migration tool. it failed as i have a filevault on old mac. so called apple support, followed instructions after 8 hours of copying file accross to the new mac all seemed fine. great it works now lets go and enable filevault. done in 30 min.

Ok All good so far.

Lets refresh the system witha reboot.

now i reboot, get a login screen with the user account. great all good right...NO!

after login I get the Apple logo and the curso and nothing happens! at all. rebooted several times, used disck utility and no joy. call apple ...offcourse they are closed at its 11:30pm at night in UK.... what to do...after 4 days of trying to get my data accross to a new machine thats costed a fortune. and countless hours of my personal time i am stuck and prity ****** off.

Searched forums nothing online that solves it. I hope there is someone here who can shed some light on this?