You can contact their customer service by phone.
You can go directly to the headquarters and provide some information about your cooperation with him at that time, such as the signed agreement, but don't give them the original to handle the amount.
This is the risk of going to the platform. While you can get the free advertising effect on the platform, you are also bound by the platform, especially those who can't let customers directly transfer money into their accounts and need to go to the platform to withdraw money. Actually, this is the case. You are very passive in the back, and you have to follow the direction of the platform. It is better to make a platform for yourself and refer to three meals.