I hired an indian company to do some work on three sites that I own. I used a freelancing platform and they have been banned and now when i check in my wordpress sites, the admin user will not delete. Everytime i try and delete them it comes back. I change the password and the email address, but when i check a couple of hours later it comes back again, giving them full control over my sites which they are playing around with. any help would be great.

I have tried going into the cpanel but it still will not delete. my hosting company has tried to delete them but it is not working