Exchange2013 OWA user disabled but still can access mailbox

It definitelly does not work as expecting..

I have disabled for ONE user OWA in ECP web console, but user has still access to hit mailbox via OWA..

I run iisreset, waited couple days (doing some different things of :horse :) .. but still no luck.

Also tryied some powershell cmd, disabled alost everything.. he still can login..

Set-CASMailbox -Identity "my user" -OWAEnabled $False ..

also same with Ews, Ecp .. no luck

any idea ?

My goal : just like in SBS2008 i have to disable OWA for all users and enable for few of them..