There are reasons why you are still banned.
First Reason is that even if you got banned at 11:59pm of Jan 1, it does not mean you will be unbanned on 12:01am of Jan 2. If it is 24 hours, you must wait until 11:59 OF JAN. 2.
Second Reason is all bans won't end at the exact time. You can wait 15-45mins. or so until you get unbanned.