1. According to regulations, you should have a contract, because you are Party B of the loan contract. The handling bank must have a contract, not a contract. You can keep an eye on the handling bank and ask them to give you the contract; If there is no original, you can ask for a copy and affix the bank seal, which has the same legal effect as the original contract.

2. If the handling bank really doesn't have the original copy for you, try to make a copy at the city branch (you can ask the handling bank to issue a certificate and bring your ID card) and let the city branch or the handling bank stamp it.

You can sign a new contract.

4. If there is really no way, there is a copy in the local real estate trading center (Housing Authority). You can ask the developer to make a copy there for you. Although there is no "red seal" of the bank, it is better to talk than nothing.