Cultural communication companies are allowed to pay the deposit, but the contract stipulates that the deposit will be returned unconditionally for a period of three months. Is this credible?

Not credible. When concluding a contract, you must carefully consider how to protect your own interests if the other party fails to perform its obligations in accordance with the specific terms of the contract. In other words, what can you do to protect yourself when your contractual benefits cannot be realized? If the other party breaches the contract and there is nothing you can do, then you should not sign the contract. If you are reduced to the other person's personality as a guarantee, you can't expect to get benefits. I've figured it out. If you can't get the contract benefits, you can admit it yourself.