If you want to apply for a refund on Tian Tian Fitness app, you can follow the following steps:

1. Open the Everyday Fitness app and enter the customer service center.

2. Click "Contact Customer Service" and explain to the customer service why you want a refund.

3. Wait for customer service review. After the approval, the refund will be automatically received.

Please note that the specific refund process may vary depending on the version or region of the app. It is recommended that you check the relevant guides in the application or contact customer service for more details.