When gifted with a promo code by Quidax, as per the terms of use of the code, you are required to trade the value before you can withdraw it.
This means, if you are awarded a 1,000 Naira promo code and want to withdraw Naira, you have to buy any of the available cryptocurrencies. Note that you can transfer our cryptocurrency bought. Although, you would need to sell it for Naira before you can withdraw it.
It's important to note that you can only withdraw to the tune of your promo balance that has been traded.
i.e If you have a N1,000 promo balance loaded and deposit further N4,000, the maximum amount you can withdraw is N4,000 until you trade with the promo value.