Legal analysis: Long-term arrears of payment are common civil disputes. With written proof of receipt, the creditor can prove how many transactions actually occurred, either with the receipt or in combination with the sales contract. If you violate the contract, you may be required to pay the purchase price and liquidated damages, which constitutes a breach of contract. You may entrust a lawyer to file a lawsuit in a people's court in accordance with the law. Anyone who is capable of executing a judgment or ruling of a people's court but refuses to execute it, if the circumstances are serious, shall be sentenced to fixed-term imprisonment of not more than three years, criminal detention, or a fine.

Legal basis: Article 577 of the "People's Republic of China and Civil Code" If a party fails to perform its contractual obligations or the performance of its contractual obligations does not comply with the agreement, it shall be responsible for continuing the performance, taking remedial measures, or Liability for breach of contract such as compensation for losses.