When will you be notified for PMP audit

I read some discussion saying you will be notified as soon as you paid the fee.

Does it mean if I don't receive anything immediately, then i'm not selected?

Yes, PMI randomly selects (about 10%) of people for Audit when you pay the Exam Fee. If you are caught an audit within 2 minute you will receive this email and your exam eligibility will be kept on hold until you clear the Audit. If you have not seen any such communication from PMI after paying the exam fee, it means you are free from the Audit.

Rohit, PMP

Technically, you can be audited anytime between your fee payment date and certification expiration date. But usually the audit happens immediately after you have paid the fees. You can read more about audit in this FAQ.