According to relevant laws, the elements that constitute a fundamental breach of contract are:
1, damage caused by breach of contract;
2. The damage deprives the buyer of significant interests;
The consequences of the damage are foreseeable by the seller, including when signing the contract.
Fundamental breach of contract specifically includes the following three contents:
1. The seller's non-delivery, delayed delivery or inconsistent delivery or defective ownership constitute a fundamental breach of contract;
2. The seller declares that it will not fulfill the delivery obligation within the specified time;
3. The buyer fails to perform the contract after the expiration of the grace period.
When the seller breaches the contract, the buyer may terminate the contract under the following circumstances:
1, the seller breached the contract fundamentally.
2. If the seller fails to deliver the goods, the seller fails to deliver the goods within a reasonable time or declares that he will not deliver the goods.
When the seller delivers the goods. If the seller has delivered the goods, the buyer loses the right to terminate the contract:
(1) If the delivery is delayed, the buyer will announce the termination of the contract within a reasonable time after learning of the delivery;
(2) If the delivery is inconsistent, the buyer proposes to terminate the contract within a reasonable time after inspecting the goods;
(3) after the expiration of the grace period given to the seller to perform the contract or make remedies, or within a reasonable time after refusing to accept the seller's performance of obligations, announce the termination of the contract.
(4) The notice of the buyer's termination of the contract only takes effect when the notice is sent to the seller.
To sum up, when part of the goods delivered by the seller meet the requirements of the contract, the buyer shall accept the part that meets the requirements; Only when the seller's complete non-delivery or non-delivery as stipulated in the contract constitutes a fundamental breach of the contract can one party declare the whole contract null and void. When the quantity delivered by the seller is greater than the quantity stipulated in the contract, the buyer has the right to choose, accept or reject all the overpayments.
Legal basis:
Article 598 of the Civil Code of People's Republic of China (PRC)
The seller shall perform the obligation of delivering the subject matter to the buyer or delivering the documents for extracting the subject matter, and transfer the ownership of the subject matter.
Article 599
The seller shall deliver the relevant documents and materials other than the documents for taking delivery of the subject matter to the buyer in accordance with the agreement or trading habits.
Article 600
Where the subject matter with intellectual property rights is sold, the intellectual property rights of the subject matter do not belong to the buyer, except as otherwise provided by law or agreed by the parties.
Article 60 1
The seller shall deliver the subject matter at the agreed time. If the delivery period is agreed, the seller may deliver the goods at any time within the delivery period.