Sorry to hear about your H1B denial.
Unfortunately, you have zero days to leave US after the denial, if your i94 has already expired.
You can fileH1B transfer but cannot stay in US as i94 has already expired and H1B extension has been denied.
You should wait for result outside US and come back once the H1B petition is approved.
The normal time that is normally considered okay to leave US is about 10-15 calendar days (not business days).
But, please note that you will still need to mention this time as overstay time in all your future US visa applications (on DS160) along with the legitimate reason.