The NairaEx order system is instant and automated. You should receive the bitcoin immediately in your address after completing the order and the Naira sent to your bank account after the bitcoin has reached 2 confirmations.
Bank networks could delay order processing.
Your coin deposit must reach certain confirmation numbers before processing begins.
Each confirmation takes between a few seconds and 90 minutes, with 10 minutes being the average. If the transaction is sent with low fees or the blockchain network is busy, confirmation can take much longer.