My entire battle net account has been banned and I have no idea why nor am i able to find out why. When I try to login, all it says is "Your Blizzard Account is banned
When action is taken against an account, an email is sent to the registered email address. Sometimes spam filters can nab it so be sure to check.
If there is no email, you need to submit an appeal ticket. This will accomplish two things. 1) The reply should include the catagory that the ban was applied under (it won’t go into detail). 2) The GM that is assigned to your ticket will review the circumstances and either uphold the ban or reverse it if a mistake was made.
It’s also possible that your account was hacked and closed for safety reasons. If that’s the case, you can submit a hacked account ticket to have it investigated. Be sure to follow the directions on that page to resecure your system.