The bank loan contract has also been signed, and now the bank staff calls to say that the bank has changed the contract format and needs to sign it again.
Not credible. Generally speaking, bank loan contracts are required to be signed in person and must be signed in the public area of the bank. Even if it is lost, it is the responsibility of the bank. You can ask the bank for details. Now that the bank has said that they didn't call, you don't have to pay attention to the person who refused to call.