If you handle it yourself, you need to send it by registered mail in about 2 weeks. The address must be correct and someone will sign for it. If the agency handles it, you can go directly to pick it up and get it on the same day.
So rejection notices outside Beijing usually arrive in about a week. Please pay attention to the postmark date of your local post office. This is very important for your rights. There is no fixed one. It is better to entrust an agency to handle the registration. Just ask the agency to contact you as soon as the trademark is rejected.