Hi Yasmin,
First clutches almost always fail, so this is perfectly normal. If the pair is still sitting on the eggs, leave them alone and they will usually abandon the eggs or push them aside when they are past due. If you are 100% sure they are not fertile, then once the due date comes and goes, keep a close watch, and if the pair pushes the eggs aside, or abandons them, or if you observe the pair mating again, go ahead and remove the nest box. You should always rest your pair for 6 months after each clutch, whether the eggs hatch or not. Remove the nest box, move the cage to a busy place in the house, and make sure the birds only get 8-10 hours of light each day, by covering the cage early each evening. In 6 months, return the nest box, give them their privacy again and longer periods of light each day. Sometimes second clutches fail, but if they get through a 3rd clutch with still no results, then for some reason the birds aren’t suitable for breeding.
Thank you for asking Lafeber,
Brenda