How long is under review

Ive recently sold an item and the item has been under review for over a day and admin said its 24hrs then item is back on sale. My item is still under review how long will it take?

I apologize for any inconvenience that this has caused. This processes can take up to 48hrs depending on how quickly the Buyer can send us the appropriate information that we require to approve the payment. This is for all parties protection involved in the transaction.