There is a foreign currency debt, and I originally wanted to save money to purchase foreign exchange in a RMB account to repay it. But it's all used to pay off the debts of RMB accounts.

This is not a question of whether the regulations are reasonable. I think when you applied for credit, the bank had written these on the credit card application form. Since you applied for the card, it means that you accepted these terms, but you didn't see the mistake clearly. How can the bank computer tell the purpose of your RMB deposit? Bank robbery? Joke! Just buy foreign exchange and deposit it. Think twice before you act in this situation!