After the seller completed the supply as agreed, the buyer failed to fulfill the payment obligation. The seller is the creditor and the buyer is the debtor. A debtor is a person who has an obligation to do or not do something to the other party. The main body of debt includes two parties, namely the creditor and the debtor. In a debt relationship, both the creditor and the debtor must be specific. The debtor can be one person or more than one person.

Provisions for debt joining:

Debt joining, also known as co-occurrence debt commitment, means that the original debtor is not divorced from the original debt relationship, and a third person joins the original debt relationship and shares the debt with the debtor.

Legal requirements:

The elements that constitute debt consolidation are:

1. The third party and the debtor agree that the third party will join the debt and share the debt with the debtor;

2. The third person or the debtor notifies the creditor, or indicates to the creditor that the third person is willing to join the debt and share the debt with the debtor;

3. The creditor agrees, or fails to explicitly refuse within a reasonable period. Those who meet these three conditions constitute debt joining.

The effect of debt joining is:

1, the effect on creditors, the creditor's rights are further protected through the addition of debts, and creditors can claim rights from the original debtor or a third party, but only enjoy one creditor's rights, not two;

2. As for the validity of the original debtor, the third party promises to perform the original debt only for the third party. The original debtor is not divorced from the original creditor-debtor relationship, and still has the obligation to perform the contract to the creditor, and still enjoys the reasonable defense right to the creditor;

3. The effect on the third party is that the third party becomes a debtor, assumes obligations to the creditor together with the original debtor, and can exercise the defense of the original debtor against the creditor;

4. The influence on the relationship between the third party and the original debtor is that the third party and the debtor are jointly and severally liable to the creditors, that is, the third party and the debtor are jointly and severally liable within the scope of the debts they are willing to bear.

Legal basis: Article 595 of the Civil Code of People's Republic of China (PRC)? A sales contract is a contract in which the seller transfers the ownership of the subject matter to the buyer and the buyer pays the price.

Article 596? The contents of a sales contract generally include terms such as name, quantity, quality, price, time limit for performance, place and method of performance, packaging method, inspection standards and methods, settlement method, language used in the contract and its effectiveness.