Notice of delivery of property in installments

This is a breach of contract. As long as there is no actual delivery, it is a breach of contract.

According to the provisions of the national house purchase contract:

1) If the delivery is overdue within 30 days, the seller (developer) shall pay the buyer 0.3 ‰ of the paid house price as penalty per day from the second day of the stipulated delivery time to the actual delivery date, and continue to perform the contract;

2) If the delivery time exceeds 30 days, the buyer has the right to terminate the contract. The seller (developer) must return all the payment to the buyer within 30 days upon the buyer's application for cancellation of house purchase, and pay 1% of the payment as penalty to the buyer.

These are clearly written in your contract, just have a look if you have nothing to do. You should protect your own interests. In this case, the developer basically gives the owner some money or reduces the property fee. I hope my answer can help you.